JP4670966B2 - Printing apparatus and printing method - Google Patents

Description

  The present invention relates to a printing apparatus and a printing method that perform printing with different amounts of medium transport.

  2. Related Art Printing apparatuses such as printers, plotters, and facsimiles include an ink jet type that prints an image on a medium using ink ejected from nozzles. In this printing apparatus, an ink discharge operation for intermittently discharging ink while moving the head and a transport operation for transporting the medium in a direction crossing the moving direction of the head are alternately performed, whereby an image is printed on the medium. Printing.

  Some printing apparatuses of this type perform printing with different carry amounts. For example, in order to expand the area where an image is printed, there is a type in which printing is performed with a conveyance amount at a terminal portion of a medium being smaller than a conveyance amount at an intermediate portion (for example, see Patent Document 1). In this printing apparatus, the conveyance amount switching timing is determined based on the size of the medium to be printed. For example, the transport amount is switched on condition that the number of passes from the start of printing (corresponding to the number of times the head has been moved in the moving direction) has reached a specified number.

Japanese Patent Laid-Open No. 7-242025

  Some printing apparatuses of this type are provided with a sensor for detecting a medium upstream of the head in the medium conveyance direction. In this printing apparatus, when the end of the medium is detected by the sensor, printing is completed after the specified number of passes, and the medium is ejected. In this printing apparatus, the control of the carry amount is not linked with the detection of the end of the medium. For this reason, a problem may occur when the length of the medium to be printed is different from the length of the medium designated for control. For example, when the medium to be printed is shorter than the medium designated for control in terms of the length in the medium conveyance direction, the medium remains in a state where unprinted portions that are long in the moving direction of the head remain in some places. Will be discharged. Also, in borderless printing, if the medium to be printed is longer than the medium specified for control, the number of times the medium is transported with a small transport amount will increase, and the printing time will be increased accordingly. Will become longer.

  The present invention has been made in view of such problems, and an object of the present invention is to prevent inconveniences when the size of a control medium is different from the size of a medium to be printed.

The main invention for achieving the object is as follows:
A transport mechanism for transporting the medium;
A nozzle row composed of a plurality of nozzles arranged in the medium conveying direction;
A nozzle row moving mechanism for moving the nozzle row in a direction crossing the medium conveyance direction;
A sensor that is disposed upstream of the nozzle row in the medium conveyance direction and detects the end of the medium;
A controller for controlling conveyance of a medium by the conveyance mechanism, movement of a nozzle row by the nozzle row movement mechanism, and ejection of ink from the nozzle row;
Causes repeated a dot forming operation of ejecting ink from the nozzles while moving the nozzle line transport operation and which Ru is conveyed to the medium in the first transport amount, monitor the detection signal from the sensor,
When the end of the medium is detected by the sensor, the number of repetitions of the transport operation and the dot forming operation until the end of the medium reaches the transport amount switching position is determined.
After the transport operation and the dot forming operation are performed a predetermined number of times, the transport operation for transporting the medium with the second transport amount smaller than the first transport amount and the dot forming operation are performed. A controller,
Is a printing apparatus.
Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

1 is a diagram illustrating a configuration of a printing system 100. FIG. 2 is a block diagram illustrating configurations of a computer 110 and a printer 1. FIG. FIG. 3A is a perspective view illustrating the configuration of the printer 1 of the present embodiment. FIG. 3B is a side view illustrating the configuration of the printer 1 of the present embodiment. FIG. 4A is a plan view of the platen 24. FIG. 4B is an enlarged perspective view showing a part of the platen 24. 4 is a cross-sectional view for explaining the structure of a head 41. FIG. FIG. 5 is a diagram for explaining an arrangement of nozzles Nz included in a head 41. It is a figure for demonstrating drive signal COM and application control of drive signal COM. 10 is a flowchart for explaining an operation on the computer 110 side during the execution period of a printing operation. 4 is a flowchart for explaining the operation of the printer 1 during printing. It is explanatory drawing of an interlace system. FIG. 11A is a conceptual diagram for explaining conveyance amount switching control. FIG. 11B is a timing chart for explaining the relationship between the control signal for the conveyance motor 22 and the detection signal from the paper detector 53. FIG. 11C is a conceptual diagram illustrating the position of the end of the sheet S. 4 is a conceptual diagram for explaining a position of a terminal end of a sheet S. FIG.

=== Summary of disclosure ===
At least the following matters will become clear from the description of the present specification and the accompanying drawings.

That is, a transport mechanism for transporting a medium, a nozzle array composed of a plurality of nozzles arranged in the medium transport direction, and arranged upstream of the nozzle array in the medium transport direction to detect the end of the medium And a controller for controlling the conveyance of the medium by the conveyance mechanism and the ejection of the ink from the nozzle row, after the medium is conveyed by a first conveyance amount and printing on the medium is performed. The medium is transported by a second transport amount that is smaller than the first transport amount, printing is performed on the medium, and the first end is detected according to a detection result of the end of the medium by the sensor. And a controller that determines a timing for switching from the carry amount to the second carry amount.
According to such a printing apparatus, the timing for switching from the first transport amount to the second transport amount is determined according to the detection result of the end of the medium by the sensor, and at this timing, the first transport amount is determined from the first transport amount. Switching to the second transport amount is performed. For this reason, even if the size of the medium to be printed is different from the size of the medium designated for control, proper printing can be performed.

In such a printing apparatus, an ink receiving portion that is provided at a position facing a part of the plurality of nozzles located upstream in the medium conveyance direction and receives ink that has not landed on the medium, Have more.
According to such a printing apparatus, when performing so-called borderless printing, it is possible to prevent a problem that the inside of the apparatus becomes dirty even if the sizes of the media are different.

In this printing apparatus, the controller acquires the position of the end of the medium based on a detection result of the end of the medium by the sensor, and the acquired position of the end of the medium is upstream in the medium conveyance direction. Printing on the medium is stopped when the printing position of a part of the nozzles is exceeded.
According to such a printing apparatus, the printing time can be shortened.

In this printing apparatus, the controller acquires the position of the end of the medium based on the detection result of the end of the medium by the sensor, and the acquired position of the end of the medium is switched to a predetermined conveyance amount. Switching from the first transport amount to the second transport amount at the timing when the position is reached.
According to such a printing apparatus, the timing for switching from the first transport amount to the second transport amount can be optimized.

In this printing apparatus, the conveyance amount switching position is based on a conveyance amount necessary for printing a portion that has not been printed by the printing by the first conveyance amount by printing by the second conveyance amount. It is stipulated.
According to such a printing apparatus, it is possible to optimize the printing range based on the second transport amount, and thus shorten the printing time.

In this printing apparatus, the transport amount switching position is based on the most downstream nozzle in the medium transport direction among some nozzles located on the upstream side in the medium transport direction, and the second point from the base point. The upstream position in the medium transport direction is set as the most downstream switching position by the transport amount necessary for printing by the printing by the transport amount of the medium, and the first transport amount is shifted from the most downstream switching position by the first transport amount. It must be set within the range where the upstream position is the most upstream switching position.
According to such a printing apparatus, it is possible to reliably prevent a problem that an unprinted portion remains at the end portion of the sheet.

In this printing apparatus, the transport mechanism includes a transport motor serving as a drive source when transporting the medium, and the controller detects a control signal for the transport motor and a detection result of the end of the medium by the sensor. To obtain the position of the end of the medium.
According to such a printing apparatus, since the control signal for the transport motor is used when acquiring the position of the end of the medium, the position of the end of the medium can be acquired with high accuracy without adding a special configuration.

In this printing apparatus, the second transport amount is determined based on the number of partial nozzles located on the upstream side in the medium transport direction.
According to such a printing apparatus, the second transport amount can be optimized, and as a result, the printing time can be shortened.

In this printing apparatus, the sensor includes a light emitting element and a light receiving element, and the amount of light received by the light receiving element varies depending on the presence or absence of the medium.
According to such a printing apparatus, the end of the medium can be detected with high accuracy.

Further, a transport mechanism for transporting a medium, the transport mechanism having a transport motor as a drive source when transporting the medium, a nozzle row including a plurality of nozzles arranged in the medium transport direction, A sensor disposed upstream of the nozzle row in the medium conveying direction, the sensor having a light emitting element and a light receiving element, and varying the amount of light received by the light receiving element depending on the presence or absence of the medium, thereby terminating the end of the medium A sensor that detects ink, an ink receiving portion that is provided at a position facing a part of the plurality of nozzles located upstream in the medium conveyance direction, and that receives ink that has not landed on the medium; and A controller for controlling the conveyance of the medium by the conveyance mechanism and the ejection of the ink from the nozzle row, after the medium is conveyed by a first conveyance amount and printing on the medium is performed, The medium is transported by a second transport amount that is smaller than the first transport amount, printing is performed on the medium, and a control signal for the transport motor and a detection result of the end of the medium by the sensor are used. The end position of the medium is acquired based on the first transfer amount to the second transfer amount at a timing when the acquired end position of the medium reaches a predetermined transfer amount switching position. And a controller that stops printing on the medium when the end position of the acquired medium exceeds a position printed by some nozzles located upstream in the medium conveyance direction. The transport amount switching position is based on the transport amount necessary for printing a portion that has not been printed by the printing by the first transport amount by the printing by the second transport amount. Among the nozzles located on the upstream side of the medium, the most downstream nozzle in the medium transport direction is a base point, and the transport amount necessary for printing by the second transport amount from the base point is the medium transport direction The upstream position is set as the most downstream switching position, and the upstream position in the medium transport direction by the first transport amount from the most downstream switching position is set as the most upstream switching position, It is also possible to realize a printing apparatus in which the second transport amount is determined based on the number of partial nozzles located on the upstream side in the medium transport direction.
According to such a printing apparatus, since almost all the effects described above are exhibited, the object of the present invention can be achieved most effectively.

  Further, based on a step of causing the medium to be transported by a first transport amount and performing printing on the medium, and a detection signal from a sensor that detects the end of the medium, the first transport amount is determined based on the first transport amount. A step of determining a timing for switching to a second transport amount that is smaller than the amount, and a step of switching from the first transport amount to the second transport amount at a determined timing to cause printing on the medium. A printing method can also be realized.

=== Printing System 100 ===
<Configuration of Printing System 100>
Next, the best mode for carrying out the present invention will be described. In the following description, a printing system including a printing apparatus and a printing control apparatus is taken as an example. Here, FIG. 1 is a diagram illustrating the configuration of the printing system 100.
The printing system 100 includes a printer 1 as a printing apparatus and a computer 110 as a printing control apparatus. Specifically, the computer 110, the display device 120, the input device 130, and the recording / reproducing device 140 are included. The printer 1 prints an image on a medium such as paper, cloth, or film. In addition, regarding this medium, in the following description, a sheet S (see FIG. 3A), which is a typical medium, will be described as an example. The computer 110 is communicably connected to the printer 1. In order to cause the printer 1 to print an image, the computer 110 outputs print data corresponding to the image to the printer 1. Computer programs such as application programs and printer drivers are installed in the computer 110. The display device 120 has a display. The display device 120 is for displaying a user interface of a computer program, for example. The input device 130 is a keyboard 131 or a mouse 132, for example. The recording / reproducing device 140 is, for example, a flexible disk drive device 141 or a CD-ROM drive device 142.

=== Computer 110 ===
<Configuration of Computer 110>
Next, the configuration of the computer 110 will be described. Here, FIG. 2 is a block diagram illustrating the configuration of the computer 110 and the printer 1.
The computer 110 includes the recording / reproducing apparatus 140 described above and a host-side controller 111. The recording / reproducing apparatus 140 is communicably connected to the host-side controller 111, and is attached to the housing of the computer 110, for example. The host-side controller 111 performs various controls in the computer 110, and the display device 120 and the input device 130 described above are also connected to be communicable. The host-side controller 111 includes an interface unit 112, a CPU 113, and a memory 114. The interface unit 112 is interposed between the printer 1 and exchanges data. The CPU 113 is an arithmetic processing unit for performing overall control of the computer 110. The memory 114 is used to secure an area for storing a computer program used by the CPU 113, a work area, and the like, and includes a RAM, an EEPROM, a ROM, a magnetic disk device, and the like. As described above, computer programs stored in the memory 114 include application programs and printer drivers. The CPU 113 performs various controls according to the computer program stored in the memory 114.

  The printer driver causes the computer 110 to realize a function of converting image data output from the application program into print data. Then, the printer 1 performs printing on the paper S by receiving print data from the computer 110. In other words, it can be said that the computer 110 controls the operation of the printer 1 via the print data. Therefore, the computer 110 functions as a print control apparatus by this printer driver. The printer driver has a code for realizing a function of converting image data into print data.

  The print data is data in a format that can be interpreted by the printer 1 and includes various command data and pixel data. The command data is data for instructing the printer 1 to execute a specific operation. The command data includes, for example, command data for instructing paper feed, command data for indicating the carry amount, and command data for instructing paper discharge. The pixel data is data related to pixels of an image to be printed. Here, the pixel is a square grid virtually defined on the paper, and indicates a region where dots are formed. The pixel data in the print data is data relating to dots formed on the paper (for example, dot size data). In the present embodiment, the pixel data is composed of 2-bit data. For example, as shown in FIG. 7, the pixel data includes data [00] corresponding to no dot, data [01] corresponding to small dots, data [10] corresponding to formation of medium dots, There is data [11] corresponding to dots. Therefore, the printer 1 can express four gradations in one pixel. The printer driver performs resolution conversion processing, color conversion processing, halftone processing, rasterization processing, and the like (described later) in order to convert image data output from the application program into print data.

=== Printer 1 ===
<About the configuration of the printer 1>
Next, the configuration of the printer 1 will be described. Here, FIG. 3A is a perspective view illustrating the configuration of the printer 1 of the present embodiment. FIG. 3B is a side view illustrating the configuration of the printer 1 of the present embodiment. In the following description, FIG. 2 is also referred to.
As shown in FIG. 2, the printer 1 includes a paper transport mechanism 20, a carriage moving mechanism 30, a head unit 40, a detector group 50, a printer-side controller 60, and a drive signal generation circuit 70. In the printer 1, the control target unit, that is, the paper transport mechanism 20, the carriage moving mechanism 30, the head unit 40, and the drive signal generation circuit 70 are controlled by the printer-side controller 60. As a result, the printer-side controller 60 prints an image on the paper S based on the print data received from the computer 110. Each detector in the detector group 50 monitors the status in the printer 1. Each detector outputs the detection result to the printer-side controller 60. Upon receiving the detection results from each detector, the printer-side controller 60 controls the control target unit based on the detection results.

<About the paper transport mechanism 20>
The paper transport mechanism 20 corresponds to a transport mechanism for transporting a medium. The paper transport mechanism 20 transports the paper S by a predetermined transport amount in the transport direction. This transport direction is a direction that intersects the carriage movement direction described below. 3A and 3B, the paper transport mechanism 20 includes a paper feed roller 21, a transport motor 22, a transport roller 23, a platen 24, and a paper discharge roller 25. The paper feed roller 21 is a roller for feeding the paper S inserted into the paper insertion opening toward the print start position, and has a D-shaped cross-sectional shape in this example. The transport motor 22 is a drive source for transporting the paper S in the transport direction. The conveyance motor 22 of the present embodiment is configured by a direct current motor (DC motor). The transport roller 23 is a roller for transporting the paper S sent by the paper feed roller 21 in the transport direction. The operation of the transport roller 23 is also controlled by the transport motor 22. The paper discharge roller 25 is a roller for carrying the paper S that has been printed.

  The platen 24 is a member that supports the paper S being printed from the back side of the paper S. Here, FIG. 4A is a plan view of the platen 24. FIG. 4B is an enlarged perspective view showing a part of the platen 24. The platen 24 is provided with an ink receiving groove 241 for receiving ink that has not landed on the paper S. The ink receiving groove 241 is a groove-like portion having an opening surface facing the head, and is provided at a position facing the nozzle of the head. The positional relationship between the ink receiving groove 241 and the nozzle will be described later. The ink receiving groove 241 is provided with an ink absorbing member 242 for absorbing ink. The ink absorbing member 242 is made of a member that can absorb a liquid such as a sponge. A plurality of protrusions 243 are provided on the platen 24 so that the ink absorbing member 242 and the paper S are not in direct contact with each other. The protrusion 243 protrudes upward (head side) from the surface of the ink absorbing member 242, and the front end surface thereof contacts the back surface of the paper S.

<About the carriage moving mechanism 30>
The carriage moving mechanism 30 is for moving the carriage CR to which the head unit 40 is attached in the carriage moving direction. The carriage movement direction includes a movement direction from one side to the other side and a movement direction from the other side to the one side. The head unit 40 has a head 41, and the head 41 has a nozzle row (Nk to Ny) constituted by a plurality of nozzles Nz (see FIGS. 5 and 6). For this reason, the carriage movement direction corresponds to the movement direction (predetermined direction) of the nozzle row in which the nozzle row moves. Therefore, the carriage moving mechanism 30 corresponds to a nozzle row moving mechanism that moves the nozzle row in a predetermined direction.

  The carriage moving mechanism 30 includes a carriage motor 31, a guide shaft 32, a timing belt 33, a driving pulley 34, and a driven pulley 35. The carriage motor 31 corresponds to a drive source for moving the carriage CR. The operation of the carriage motor 31 is controlled by the printer-side controller 60. A drive pulley 34 is attached to the rotation shaft of the carriage motor 31. The drive pulley 34 is disposed on one end side in the carriage movement direction. A driven pulley 35 is disposed on the other end side in the carriage movement direction on the opposite side to the drive pulley 34. The timing belt 33 is connected to the carriage CR and is spanned between a driving pulley 34 and a driven pulley 35. The guide shaft 32 supports the carriage CR in a movable state. The guide shaft 32 is attached along the carriage movement direction. Accordingly, when the carriage motor 31 operates, the carriage CR moves along the guide shaft 32 in the carriage movement direction.

<About the head unit 40>
The head unit 40 is for ejecting ink toward the paper S. The head unit 40 is attached to the carriage CR. The head 41 included in the head unit 40 is attached at a position facing the platen 24. The head control unit 42 included in the head unit 40 is provided inside the case.

  Next, the structure of the head 41 will be described. Here, FIG. 5 is a cross-sectional view for explaining the structure of the head 41. FIG. 6 is a diagram for explaining the arrangement of the nozzles Nz included in the head 41. The illustrated head 41 has a series of ink flow paths from the ink storage chamber 411 through the pressure chamber 412 to the nozzle Nz. The ink flow paths are provided in a number corresponding to the nozzles Nz. A piezoelectric element 414 is provided on the diaphragm 413 that partitions a part of the pressure chamber 412. The piezo element 414 is provided on the surface of the diaphragm 413 opposite to the pressure chamber 412 and deforms the diaphragm 413 according to the potential difference. Since the ink flow path is filled with ink, ink can be ejected from the corresponding nozzle Nz by deformation of the vibration plate 413. Such a piezo element 414 corresponds to an element capable of executing an operation for ejecting ink.

  In the head 41, the nozzles Nz are arranged in the transport direction of the paper S at a predetermined pitch, and constitute a nozzle row. The formation pitch of the nozzles Nz is represented by k · D. Here, D is a minimum dot pitch in the transport direction, that is, an interval at the highest resolution of dots formed on the paper S. K is a coefficient representing the relationship between the minimum dot pitch D and the nozzle pitch, and is set to an integer of 1 or more. For example, when the nozzle pitch is 180 dpi (1/180 inch) and the dot pitch in the transport direction is 720 dpi (1/720 inch), the coefficient k is 4. In the example shown in the figure, the nozzles Nz of each nozzle row are assigned a lower number as the nozzles Nz on the downstream side (# 1 to # 180). That is, the nozzle Nz (# 1) is located downstream of the nozzle Nz (# 180) in the transport direction, that is, on the start end side of the sheet S. A plurality of nozzle rows are provided at different positions in the carriage movement direction (nozzle row movement direction). Further, the head 41 can determine the type of ink to be ejected for each nozzle row. The head 41 starts from the left side of FIG. 6 with a first nozzle row Nk that discharges black ink, a second nozzle row Nc that discharges cyan ink, a third nozzle row Nm that discharges magenta ink, and yellow ink. And a fourth nozzle row Ny to be ejected.

  The ink receiving groove 241 described above is provided in the entire range in which the carriage CR can move on the downstream side and the upstream side in the transport direction. In the ink receiving groove 241, a portion located on the downstream side in the transport direction faces nozzles Nz (# 1) to nozzle Nz (# 35), and a portion located on the upstream side in the transport direction is nozzles Nz (# 145). Facing the nozzle Nz (# 180). Therefore, when the ink ejected from the nozzles Nz (# 1) to Nz (# 35) and the nozzles Nz (# 145) to Nz (# 180) does not land on the paper S, It is landed on the absorbing member 242 and absorbed. As a result, the problem that the inside of the printer 1 is soiled can be prevented.

  In the following description, for convenience, the downstream portion of the ink receiving groove 241 in the transport direction is also referred to as a downstream ink receiving groove 241a, and the upstream portion of the transport direction is also referred to as an upstream ink receiving groove 241b. The upstream ink receiving groove 241 b corresponds to an ink receiving portion that receives ink that has not landed on the paper S during printing on the terminal portion of the paper S. The ink receiving groove 241 is also provided at a position corresponding to the side edge of the standardized paper S. For example, it is provided along the transport direction at a position corresponding to the side edge of A4 size paper S, B5 size paper S, and postcard size paper S. The nozzles Nz (# 1) to Nz (# 35) facing the downstream ink receiving groove 241a are nozzle groups used when printing the starting end portion of the paper S in borderless printing. Hereinafter, these nozzles Nz are collectively referred to as a start end processing nozzle group. Similarly, the nozzles Nz (# 145) to Nz (# 180) facing the upstream ink receiving groove 241b are nozzle groups used when printing the end portion of the paper S in borderless printing. Hereinafter, these nozzles Nz are collectively referred to as a termination processing nozzle group.

<Regarding the detector group 50>
The detector group 50 is for monitoring the status of the printer 1. As shown in FIGS. 3A and 3B, the detector group 50 includes a linear encoder 51, a rotary encoder 52, a paper detector 53, and a paper width detector. The linear encoder 51 is for detecting the position of the carriage CR in the carriage movement direction. The rotary encoder 52 is for detecting the rotation amount of the transport roller 23. The paper detector 53 is for detecting the paper S to be printed. The paper width detector 54 is for detecting the width of the paper S to be printed.

  In the present embodiment, the paper detector 53 is configured by an optical sensor having a light emitting element and a light receiving element. In the paper detector 53, the amount of light received by the light receiving element is made different depending on whether or not the paper S is present. For example, when the paper S is present, the light receiving element receives reflected light from the paper S, and when the paper S is exhausted, the light receiving element does not receive the reflected light. That is, the level of the detection signal from the paper detector 53 changes at the timing when the leading edge and the trailing edge of the sheet S pass. Accordingly, the paper detector 53 corresponds to a sensor that detects the start and end of the paper S. By monitoring the level of the detection signal from the paper detector 53, the printer-side controller 60 can know the timing at which the leading edge and trailing edge of the sheet S have passed. Regarding the paper detector 53, when the paper S is present, the light may be blocked by the paper S so that the light receiving element does not receive the light. The paper detector 53 is arranged upstream of the head 41 (nozzle row). For this reason, the printer-side controller 60 can recognize the start and end positions of the paper S before printing.

<About the printer-side controller 60>
As described above, the printer-side controller 60 controls the printer 1. For example, the printer-side controller 60 controls the conveyance of the paper S by controlling the rotation amount of the conveyance motor 22. The printer-side controller 60 controls the movement of the carriage CR by controlling the rotation of the carriage motor 31. That is, the printer-side controller 60 alternately performs an operation of transporting the paper S by a predetermined transport amount and an operation of intermittently ejecting ink while moving the carriage CR (head 41). Is printing an image. As shown in FIG. 2, the printer-side controller 60 includes an interface unit 61, a CPU 62, a memory 63, and a control unit 64. The interface unit 61 exchanges data with the computer 110 which is an external device. The CPU 62 is an arithmetic processing unit for performing overall control of the printer 1. The memory 63 is for securing an area for storing a program of the CPU 62, a work area, and the like, and is configured by a storage element such as a RAM, an EEPROM, or a ROM. Then, the CPU 62 controls each control target unit according to the computer program stored in the memory 63. For example, the CPU 62 controls the paper transport mechanism 20 and the carriage moving mechanism 30 via the control unit 64. That is, a control signal for the transport motor 22 and the carriage motor 31 is output. Further, the CPU 62 outputs a head control signal for controlling the operation of the head 41 to the head control unit 42, and outputs waveform information for generating the drive signal COM to the drive signal generation circuit 70.

<About the drive signal generation circuit 70>
The drive signal generation circuit 70 generates a drive signal COM applied to the piezo element 414 based on the waveform information output from the printer-side controller 60. Here, FIG. 7 is a diagram for explaining the drive signal COM and the application control of the drive signal COM. The illustrated drive signal COM includes four waveform portions within one repetition period. Each waveform portion includes one drive pulse. That is, the first waveform portion SS1 includes the first drive pulse PS1, and the second waveform portion SS2 includes the second drive pulse PS2. The third waveform portion SS3 includes a third drive pulse PS3, and the fourth waveform portion SS4 includes a fourth drive pulse PS4. Here, the first drive pulse PS1, the third drive pulse PS3, and the fourth drive pulse PS4 have the same shape. When one of the drive pulses is applied to the piezo element 414, a predetermined amount (for example, 7 pl) of ink is ejected from the corresponding nozzle Nz. When two drive pulses are applied to the piezo element 414, double the amount of ink is ejected. That is, the amount of ink ejected increases as the number of applied drive pulses increases. On the other hand, the second drive pulse PS2 is a drive pulse used when ink is not ejected. When the second drive pulse PS2 is applied to the piezo element 414, the meniscus (the free surface of the ink exposed by the nozzle Nz) vibrates to the extent that ink is not ejected. By such vibration, the ink in the vicinity of the nozzle is agitated, thereby preventing the ink from thickening.

  The head controller 42 determines a waveform portion to be applied to the piezo element 414 based on the pixel data sent as print data. Briefly, when the pixel data is data [00] corresponding to no dot, the head control unit 42 applies only the second waveform portion SS2 to the piezo element 414. When the data is [01] indicating the formation of small dots, the head controller 42 applies only the third waveform portion SS3 to the piezo element 414. Similarly, the head controller 42 applies the third waveform portion SS3 and the fourth waveform portion SS4 to the piezo element 414 when the pixel data is data [10] indicating the formation of medium dots, and the pixel data is In the case of data [11] indicating the formation of large dots, the first waveform portion SS1, the third waveform portion SS3, and the fourth waveform portion SS4 are applied to the piezo element 414. By performing this control, the printer 1 expresses four gradations in one pixel.

=== Printing operation ===
<Operation on the computer 110 side>
First, the operation on the computer 110 side will be described. FIG. 8 is a flowchart for explaining the operation on the computer 110 side during the execution period of the printing operation. The operation on the computer 110 side is executed by the host-side controller 111 based on the printer driver. Therefore, the printer driver has a code for executing each operation.

  In this operation, the host-side controller 111 sequentially performs resolution conversion processing (step S10), color conversion processing (step S20), halftone processing (step S30), and rasterization processing (S40). Note that these processes are performed in a state where the user connects the printer 1 to the computer 110 so as to be communicable and uses the printing system 100 described with reference to FIG. Specifically, it is performed on the condition that a print execution operation has been performed from the screen of the user interface of the printer driver in a state where necessary information such as print image quality and paper size has been input. Hereinafter, each process will be described.

  Resolution conversion process (S10): The resolution conversion process is the resolution when printing the image data (text data, image data, etc.) output from the application program on the paper S (the interval between dots when printing). , Also referred to as print resolution). For example, when the print resolution is specified as 720 × 720 dpi, the host-side controller 111 converts the image data received from the application program into image data having a resolution of 720 × 720 dpi. Examples of this conversion method include interpolation and thinning of pixel data. Note that each pixel data in the image data is data having gradation values in multiple stages (for example, 256 stages) represented by an RGB color space. Hereinafter, the pixel data having RGB gradation values is referred to as RGB pixel data, and image data composed of the RGB pixel data is referred to as RGB image data.

  Color conversion process (S20): The color conversion process is a process for converting each of the RGB pixel data of the RGB image data described above into data having gradation values of multiple levels (for example, 256 levels) represented by the CMYK color space. is there. Here, CMYK is the ink color of the printer 1. That is, C means cyan. M represents magenta, Y represents yellow, and K represents black. Hereinafter, the pixel data having CMYK gradation values is referred to as CMYK pixel data, and the image data composed of these CMYK pixel data is referred to as CMYK image data. This color conversion process is performed, for example, by referring to a table in which RGB gradation values are associated with CMYK gradation values.

  Halftone process (S30): The halftone process is a process for converting CMYK pixel data having multi-stage gradation values into CMYK pixel data having small-stage gradation values that can be expressed by the printer 1. For example, CMYK pixel data indicating 256 gradation values is converted into 2-bit CMYK pixel data indicating 4 gradation values by halftone processing. As described above, the 2-bit CMYK pixel data includes data [00] corresponding to no dot, data [01] corresponding to small dots, data [10] corresponding to formation of medium dots, large data Data [11] corresponding to a dot. For such halftone processing, for example, a dither method or the like is used, and 2-bit CMKY pixel data is created so that the printer 1 can form dots dispersedly. Further, the method used for the halftone process is not limited to the dither method, and a γ correction method, an error diffusion method, or the like may be used.

  Rasterization process (S40): The rasterization process is a process for changing the CMYK image data subjected to the halftone process in the order of data to be transferred to the printer 1. The rasterized data is output to the printer 1 as the print data described above. The host-side controller 111 outputs the obtained print data to the printer 1 every time a specified amount of print data is obtained. In this embodiment, every time print data for one pass is obtained, this print data is output. The pass means an operation for moving the carriage CR once in the carriage movement direction.

<Operation on the printer 1>
Next, the operation on the printer 1 side will be described. Here, FIG. 9 is a flowchart for explaining the operation of the printer 1 during printing. Each operation described below is executed by the printer-side controller 60 controlling each control target unit in accordance with a computer program stored in the memory 63. The computer program has code for executing each operation.

  Print Command Reception (S110): The printer-side controller 60 receives a print command from the computer 110 via the interface unit 61. This print command is included in the header of print data transmitted from the computer 110. Then, the controller analyzes the contents of various commands included in the received print data, and performs the following paper feed operation, transport operation, dot formation operation, and the like.

  Paper Feed Operation (S120): If a print command is received, the printer-side controller 60 performs a paper feed operation. The paper feeding operation is a process of moving the paper S to be printed and positioning it at a printing start position (so-called cueing position). That is, the printer-side controller 60 rotates the paper feed roller 21 and sends the paper S to be printed to the transport roller 23. Subsequently, the printer-side controller 60 rotates the transport roller 23 to position the paper S sent from the paper feed roller 21 at the print start position. Note that when the paper S is positioned at the print start position, at least some of the nozzles Nz of the head 41 face the paper S.

  Dot Forming Operation (S130): Next, the printer-side controller 60 performs a dot forming operation. The dot forming operation is an operation of forming dots on the paper S by intermittently ejecting ink from the nozzles Nz that move along a predetermined direction (specifically, the carriage movement direction). The controller drives the carriage motor 31 to move the carriage CR in the carriage movement direction. In addition, the controller discharges ink from the nozzles Nz based on the print data while the carriage CR is moving. Then, when ink ejected from the nozzle Nz lands on the paper, dots are formed on the paper. That is, by this dot forming operation, a raster line composed of a plurality of dots along the moving direction of the nozzle Nz is formed on the paper.

  Transport Operation (S140): Next, the printer-side controller 60 performs a transport operation. The transport operation is a process of moving the paper S by a predetermined transport amount in the transport direction. The printer-side controller 60 drives the carry motor 22 and rotates the carry roller 23 to carry the paper S in the carrying direction. By this transport operation, the head 41 can form dots at positions different from the positions of the dots formed by the previous dot formation operation (positions in the transport direction). Here, the predetermined transport amount differs between the start and end portions of the paper S and the intermediate portion. That is, the transport amount at the start and end portions of the paper S is smaller than the transport amount at the intermediate portion of the paper S. Further, the printer-side controller 60 monitors whether or not the end of the paper S has passed through the paper detector 53 based on the detection signal from the paper detector 53 in this transport operation. The detection of the predetermined transport amount and the end of the paper S will be described later.

  Paper discharge determination (S150): Next, the printer-side controller 60 determines whether or not to discharge the paper S being printed. At the time of this determination, if data for printing on the paper S being printed remains, the paper is not discharged. Then, the printer-side controller 60 alternately repeats the dot formation operation and the conveyance operation until there is no data to be printed or until the end position of the paper S exceeds the end portion processing nozzle group. As a result, an image composed of dots (raster lines) is gradually printed on the paper.

  Paper Discharge Operation (S160): When there is no more data for printing on the paper S being printed, the printer-side controller 60 performs a paper discharge operation to discharge the printed paper S. That is, the printer-side controller 60 discharges the printed paper S by rotating the paper discharge roller 25. Note that whether or not to discharge paper may be determined based on a paper discharge command included in the print data.

  Print end determination (S170): Next, the printer-side controller 60 determines whether or not to continue printing. If printing is to be performed on the next sheet S, a feeding operation for the next sheet S is performed. If printing is not performed on the next paper S, the printing operation is terminated.

=== About the printing method ===
In the printer 1 of this embodiment having such a configuration, printing by an interlace method is performed. By using this interlace method, individual differences such as ink ejection characteristics for each nozzle Nz are dispersed on the printed image so as not to stand out. Here, FIG. 10 is an explanatory diagram of the interlace method, and illustrates an example in which the transport amount of the paper S is reduced from a midway pass. For convenience of explanation, the nozzle row shown instead of the head 41 is depicted as moving with respect to the paper S, but the paper S is actually moved in the transport direction. That is, this figure shows the relative positional relationship between the nozzle array and the paper S. Further, the number of each raster line is given for convenience. Specifically, the raster line formed most on the end side of the sheet S in pass N + 5 is indicated as r (1). In addition, in the drawing, the nozzle Nz indicated by a black circle is a nozzle Nz that actually ejects ink, and the nozzle Nz indicated by a white circle is a nozzle Nz that does not eject ink.

  In the illustrated interlace method, each time the paper S is transported in the transport direction with a constant transport amount, each nozzle Nz forms a raster line immediately above the raster line formed in the immediately preceding pass. In order to form each raster line with a constant carry amount in this way, the number of nozzles Nn (integer) that actually ejects ink is required to be coprime to the coefficient k, and the carry amount F is Nn · D is set.

  In the example of FIG. 10, the nozzle row has eight nozzles Nz arranged along the transport direction, but in order to form each raster line with a constant transport amount F, seven nozzles Nz are used. The interlace method is used for printing. Further, since seven nozzles Nz are used, the paper S is transported with a transport amount of 7 · D. As a result, for example, dots are formed on the paper S at a dot interval of 720 dpi (= D) using a nozzle row having a nozzle pitch of 180 dpi (4 · D). Then, printing using seven nozzles Nz is performed up to pass N. Then, after pass N + 1, printing is performed with a carry amount of 3 · D. Such switching of the transport amount is performed when the intermediate portion of the paper S is shifted from printing at the end portion. This is because, in the printing of the terminal portion, the nozzle Nz facing the upstream ink receiving groove 241b is used in order to prevent the ink from landing on the platen 24. In this case, the conveyance amount in the printing of the terminal portion is determined according to the number of nozzles Nz facing the ink receiving portion. This is because the nozzle Nz facing the ink receiving portion is effectively used to perform printing efficiently. As a result, it is possible to optimize the conveyance amount for the end portion processing.

  By the way, in the case of the carry amount 3 · D, normally, if three nozzles Nz are used, each raster line can be filled while keeping the carry amount constant. However, in order to complementarily form raster lines that were not formed by printing using the seven nozzles Nz, in this example, the number of nozzles Nz used is reduced stepwise. In pass N, raster lines are formed every four lines, as in raster lines r (16), r (20), and r (24). As described above, in this interlace method, a raster line immediately above the raster line formed in the immediately preceding pass is formed. Therefore, in pass N, raster lines r (16) to r (19), raster lines r (21) and r (22), raster lines r (25) and r (26), and raster line r ( 29) and r (33) remain without being formed. In order to form these raster lines, printing using six nozzles Nz is performed in pass N + 1, printing using five nozzles Nz is performed in pass N + 2, and four nozzles Nz are printed in pass N + 3. The printing used is being performed. Then, after the pass N + 4, printing using three nozzles Nz is performed.

  As described above, when the printing operation with the carry amount 7 · D is switched to the printing operation with the carry amount 3 · D, the printing operation with the carry amount 3 · D needs to be performed for a plurality of passes. For example, in order to form all the raster lines positioned on the start end side of the paper S with respect to the raster line r (16), it is necessary to perform the printing operation up to pass N + 3. Similarly, in order to form all the raster lines positioned on the start end side of the sheet S with respect to the raster line r (7), it is necessary to perform the printing operation up to pass N + 5.

<Overview of printing operations>
In the printer 1, printing is performed with the conveyance amount at both ends in the conveyance direction being smaller than the conveyance amount at the intermediate portion. When the transport amount is switched at the end portion of the paper S, the transport amount suitable for printing in the intermediate portion (corresponding to the first transport amount) is based on the detection result from the paper detector 53. , Which is also referred to as a normal processing transport amount), and a timing for switching from a transport amount suitable for printing at the end portion (corresponding to a second transport amount, hereinafter also referred to as a termination processing load). . As described above, since the end position of the sheet S is acquired and the transport amount is switched based on the acquired end position of the sheet S, the size in the transport direction of the sheet S to be printed is designated. Even if it is different from the size, printing can be performed properly. For example, it is possible to prevent a problem that printing is completed with an unprinted line remaining, or that an unnecessarily large range is printed with the conveyance amount at the end portion. Hereinafter, the printing operation will be described in detail.

<About switching the transport amount>
First, switching of the conveyance amount will be described. Here, FIG. 11A is a conceptual diagram for explaining the conveyance amount switching control. FIG. 11B is a timing chart for explaining the relationship between the control signal for the conveyance motor 22 and the detection signal from the paper detector 53. FIG. 11C is a conceptual diagram illustrating the position of the end of the sheet S. FIG. 12 is a conceptual diagram for explaining the position of the end of the sheet S. In the printer 1, the printer-side controller 60 acquires the position of the end of the paper S based on the detection result by the paper detector 53. Then, the conveyance amount switching timing is determined from the acquired end position. This switching timing is determined as the number of passes until the end of the paper S reaches the transport amount switching position when the paper S is transported by the normal processing transport amount.

  Here, the transport amount switching position will be described. In order to determine the transfer amount switching position, it is necessary to consider the following conditions. The first condition is that it is determined on the upstream side in the transport direction from the most downstream nozzle Nz (corresponding to the nozzle Nz (# 145)) in the terminal section processing nozzle group. If the transport amount switching position is set downstream of the most downstream nozzle Nz in the transport direction, the ink ejected from the nozzle Nz is detached from the downstream ink receiving groove 241a and adheres to the platen 24. Because. The second condition is that it is possible to secure a printing range (hereinafter, also referred to as a termination processing required range) based on the conveyance amount for termination processing. As described in the example of FIG. 10, in the interlace method, in order to print the end portion of the paper S without a gap, after the normal processing transport amount is switched to the termination processing transport amount, the termination processing transport is performed. It is necessary to perform multiple passes for printing by quantity. For this reason, the transport amount switching position is determined at a position where at least the print range (required range for the end portion processing) of the plural passes can be secured. The third condition is that the necessary processing range for the end portion can be secured even if the normal processing amount is conveyed.

  In consideration of the above conditions, the printer 1 has a transport amount switching position. Specifically, as shown in FIG. 11A, the position that is farthest from the base point by the necessary end part processing range from the base point to the upstream side in the transport direction with the most downstream nozzle Nz in the terminal part processing nozzle group as the base point. The downstream transport amount switching position is set. Then, a position away from the most downstream transport amount switching position by the normal processing amount transport amount upstream in the transport direction is set as the most upstream transport amount switching position. Accordingly, the range from the most downstream transport amount switching position to the most upstream transport amount switching position is determined as the transport amount switching position. Hereinafter, this range is also referred to as a conveyance amount switching range.

  Next, an operation for obtaining the end position of the sheet S will be described. As described above, in the printing operation for the intermediate portion, the paper S is transported for each normal processing transport amount. For this reason, if the detection signal from the paper detector 53 is simply monitored, the end position of the acquired paper S has a width corresponding to the normal processing transport amount. Therefore, in the present embodiment, focusing on the fact that the carry motor 22 is a DC motor, the paper S is based on the output timing of the control signal to the carry motor 22 and the timing of the level change in the detection signal from the paper detector 53. The position of the end of is detected. As shown in FIG. 11B, when the control signal to the conveyance motor 22 changes from the L level indicating stop to the H level indicating operation, the conveyance motor 22 conveys the paper S.

  Here, since the conveyance motor 22 is a direct current motor, it rotates at a rotational speed corresponding to the voltage value of the H level. For this reason, the transport amount of the paper S can be determined by the elapsed time after the control signal to the transport motor 22 is set to the H level. In each transport operation, the transport amount of the paper S is determined in advance. That is, in the printing operation for the intermediate portion of the paper S, the paper S is transported for each normal processing transport amount. Accordingly, the end position of the paper S can be acquired based on the timing td when the detection signal from the paper detector 53 changes from the L level indicating the presence of paper to the H level indicating the absence of paper. Specifically, the end of the sheet S is detected from the difference Δt between the timing tm when the control signal to the conveyance motor 22 is set to the H level and the timing td when the detection signal from the paper detector 53 is set to the H level. The conveyance amount Δm until it passes through the container 53 is acquired. Then, as shown in FIG. 11C, the position of the end of the sheet S at the time when the transport operation is finished is acquired from the difference between the transport amount Δm until passing and the transport amount for normal processing. With this configuration, the position of the end of the sheet S can be acquired with high accuracy without adding a special configuration.

  Further, the printer-side controller 60 can acquire the position of the end of the paper S for each pass based on the normal processing transport amount. For this reason, the printer-side controller 60 can also determine the number of passes until the end of the paper S reaches the transport amount switching range after the end of the paper S passes the paper detector 53. Referring to the example of FIG. 12, the printer-side controller 60 is necessary for moving from the position PE1 immediately after the end of the paper S passes the paper detector 53 to the position PE2 where the end of the paper S reaches the carry amount switching range. The correct number of passes (that is, the carry amount) can be obtained immediately after the end of the paper S passes through the paper detector 53.

<Concerning a specific example of the transport amount switching operation>
Next, a specific example of the transport amount switching operation will be described with reference to FIG. The following operation is executed by the printer-side controller 60 in accordance with the computer program stored in the memory 63. For this reason, this computer program has a code for executing the following operations.

  At the time of printing on the intermediate portion of the paper S, the printer-side controller 60 prints an image on the paper S by transporting the paper S by the normal processing transport amount (first transport amount). Here, the printer-side controller 60 monitors the detection signal from the paper detector 53 every time the carrying operation (S160, see FIG. 9) is performed. When the level of the detection signal from the paper detector 53 changes from the level indicating the presence of paper (for example, L level) to the level indicating the absence of paper (for example, H level), the printer-side controller 60 Get the end position. As described above, the printer-side controller 60 determines the timing at which the level of the control signal for the carry motor 22 is changed and the timing at which the level of the detection signal from the paper detector 53 changes (timing at which the end of the paper S passes). Based on the above, the stop position PE1 at the end of the sheet S immediately after passing is obtained.

  Further, the printer-side controller 60 acquires the number of passes necessary for the end of the paper S to reach the carry amount switching range based on the stop position PE1 and the normal processing carry amount. In this example, since the stop position PE2 after 8 passes is within the transport amount switching range, 8 passes are acquired as the required number of passes. Then, the required number of passes defines the timing for switching to the end portion processing transport amount (second transport amount). The information on the necessary number of paths is output to the computer 110. Thereby, the computer 110 changes the transport amount of the sheet S and the used nozzles Nz after the number of corresponding passes in the raster size process (S40) described above. That is, the arrangement order of the CMYK image data that has been subjected to the halftone process (S30) is determined so as to be adapted to the conveyance amount for the end portion processing.

  After that, until the predetermined number of passes are printed, in other words, the printing with the normal processing transport amount is repeated until the end position of the paper S reaches the transport amount switching range. Then, the switching timing is determined on the condition that printing of the predetermined number of passes has been performed, and the transport amount of the sheet S is changed from the normal processing transport amount to the end portion processing transport amount. In other words, the computer 110 outputs print data corresponding to the end portion processing conveyance amount to the printer 1. The printer 1 that has received this print data switches from the normal processing transport amount to the termination processing transport amount, and performs printing on the terminal portion of the paper S.

  The printer-side controller 60 also acquires the position of the end of the paper S in printing for this end portion. Here, the printer-side controller 60 monitors whether or not the end position of the paper S has exceeded the most downstream nozzle Nz (# 145) in the end portion processing nozzle group. When the end position of the sheet S exceeds the most downstream nozzle Nz (# 145), the printer-side controller 60 ends the printing operation, performs the paper discharge operation (S150), and ends the printing operation. Is output to the computer 110. The computer 110 that has received the information to end the printing operation stops the conversion of the image data into the print data. If there is image data for the next sheet S, the image data is converted into print data. If there is no image data for the next sheet S, the conversion to print data is terminated.

  The printer 1 that performs the above control has the following advantages over the conventional printer 1. That is, the timing for switching from the normal processing transport amount to the termination portion processing transport amount is determined according to the detection result of the end of the paper S by the paper detector 53, and at this timing, the normal processing transport amount is changed to the end portion processing transport amount. Switching to the transport amount is performed. For this reason, even if the size of the paper S to be printed is different from the size of the paper S designated for control, proper printing can be performed. That is, since it is switched to the end portion processing conveyance amount at a timing suitable for the length of the paper S to be printed, appropriate printing can be performed. For example, it is possible to prevent problems such as an excessive increase in the number of times of printing due to the end portion processing conveyance amount. Since the transport amount switching range is determined in consideration of the print range required for the end portion processing transport amount, the number of times of printing (pass number) at the end portion processing transport amount is optimized and processed. Time can be shortened. In addition, it is possible to reliably prevent a problem that an unprinted line remains in printing of the end portion processing conveyance amount.

=== Other Embodiments ===
In the above embodiment, the printer 1 as a printing apparatus has been described. However, the above embodiment is for facilitating the understanding of the present invention and is not intended to limit the present invention. . The present invention can be changed and improved without departing from the gist thereof, and it is needless to say that the present invention includes equivalents thereof. For example, the following embodiments are also included in the present invention.

<About the printing method>
In the above-described embodiment, for convenience of explanation, the interlace method has been described by taking a modeled nozzle row (8 nozzles) as an example. However, the interlace method is not limited to this example. An actual nozzle row is composed of a large number of nozzles Nz such as 96 or 180. For this reason, there are various interlace systems. For example, the interlace method includes an overlap method in which one raster line is assigned to a plurality of nozzles Nz. Such an interlace method is also included in the present invention.

<About the transport motor 22>
In the above-described embodiment, the conveyance motor 22 configured by a DC motor has been described as an example. However, the conveyance motor 22 may be composed of other types of motors. For example, you may be comprised with the pulse motor. In this case, on the basis of the timing at which the end of the paper S passes the paper detector 53 (the timing at which the level of the detection signal has changed) and the number of pulses applied to the carry motor 22, the printer-side controller 60 causes the printer-side controller 60 to The end position can be obtained.

<About the paper detector 53>
In the above-described embodiment, the paper detector 53 having a light emitting element and a light receiving element has been described as an example. However, the paper detector 53 may have other configurations. For example, it may be a mechanical sensor having an arm that rotates when the paper S comes into contact therewith.

1 printer, 20 paper transport mechanism, 21 paper feed roller, 22 transport motor,
23 transport roller, 24 platen, 241 ink receiving groove,
241a downstream ink receiving groove, 241b upstream ink receiving groove,
242 ink absorbing member, 243 protrusion, 25 paper discharge roller,
30 Carriage moving mechanism, 31 Carriage motor, 32 Guide shaft,
33 Timing belt, 34 Drive pulley, 35 Drive pulley,
40 head units, 41 heads, 411 ink storage chamber, 412 pressure chamber,
413 diaphragm, 414 piezo element, 42 head control unit, 50 detector group,
51 Linear encoder, 52 Rotary encoder, 53 Paper detector,
54 paper width detector, 60 printer side controller, 61 interface section,
62 CPU, 63 memory, 64 control unit, 70 drive signal generation circuit,
100 printing system, 110 computer, 111 host side controller,
112 interface unit, 113 CPU, 114 memory, 120 display device,
130 input device, 131 keyboard, 132 mouse, 140 recording / reproducing device,
141 flexible disk drive device, 142 CD-ROM drive device,
S paper, CR carriage, Nz nozzle, Nk first nozzle row,
Nc second nozzle row, Nm third nozzle row, Ny fourth nozzle row, COM drive signal,
SS1 first waveform section, SS2 second waveform section, SS3 third waveform section, SS4 fourth waveform section,
PS1 first drive pulse, PS2 second drive pulse, PS3 third drive pulse,
PS4 4th drive pulse

Claims (4)

A transport mechanism for transporting the medium;
A nozzle row composed of a plurality of nozzles arranged in the medium conveying direction;
A nozzle row moving mechanism for moving the nozzle row in a direction crossing the medium conveyance direction;
A sensor that is disposed upstream of the nozzle row in the medium conveyance direction and detects the end of the medium;
A controller for controlling conveyance of a medium by the conveyance mechanism, movement of a nozzle row by the nozzle row movement mechanism, and ejection of ink from the nozzle row;
And repeatedly performing a transport operation for transporting the medium by a first transport amount and a dot forming operation for ejecting ink from the nozzles while moving the nozzle row, and monitoring a detection signal from the sensor,
When the end of the medium is detected by the sensor, the number of repetitions of the transport operation and the dot forming operation until the end of the medium reaches the transport amount switching position is determined.
After the transport operation and the dot forming operation are performed a predetermined number of times, the transport operation for transporting the medium with the second transport amount smaller than the first transport amount and the dot forming operation are performed. A controller,
A printing apparatus. The printing apparatus according to claim 1,
The controller is
Output the information on the number of repetitions to another controller,
The other controller is
Print that determines the arrangement order to match the second transport amount with respect to the pixel data included in the print data output to the controller and used after the repeat count based on the repeat count information apparatus. The printing apparatus according to claim 1 or 2,
The transport amount switching position is
Of some of the nozzles located on the upstream side in the medium conveyance direction, the conveyance amount necessary for printing by printing with the second conveyance amount starting from the most downstream nozzle in the medium conveyance direction range only the position of the upstream side of the medium conveying direction and the most downstream of the switching positions, wherein the most upstream switching position a position upstream of the the most downstream of the switching positions the first by conveying the amount the medium conveying direction and that the printing apparatus as defined in. Dot ink is ejected from the nozzle while moving in a direction crossing the first of the medium conveying direction of the nozzle row including a plurality of nozzles arranged in the conveying operation and the medium conveying direction Ru to convey the medium conveyance amount Repeatedly performing the forming operation to perform printing on the medium;
A detection signal from a sensor that is disposed upstream of the nozzle row in the medium conveyance direction and detects the end of the medium is monitored, and when the end of the medium is detected by the sensor, the end of the medium is detected. Determining the number of repetitions of the transport operation and the dot formation operation until the transport amount switching position is reached,
Performing the transport operation and the dot forming operation for transporting the medium with a second transport amount smaller than the first transport amount after performing the transport operation and the dot forming operation for a predetermined number of repetitions; ,
A printing method comprising:

Images