JP2015168195A - Printing apparatus and printing method - Google Patents

Abstract

A printing apparatus that makes a drive waveform switching position in an image inconspicuous is provided.
A printing apparatus includes a transport unit capable of transporting a recording medium, a first nozzle array that is disposed in a direction intersecting the transport direction of the recording medium, and that ejects first ink, and a transport direction of the recording medium. A second nozzle row that is arranged in the intersecting direction and discharges a second ink different from the first ink, and a first nozzle row driving unit that drives the first nozzle row and discharges the first ink A second nozzle row driving unit that drives the second nozzle row to discharge the second ink, a driving condition of the first nozzle row driving unit, and a driving condition of the second nozzle row driving unit, A drive condition changing unit that changes at a different position of an image formed on the recording medium among positions along the conveyance direction of the recording medium.
[Selection] Figure 3

Description

  The present invention relates to an inkjet recording type printing apparatus and a printing method therefor.

  In a recording head of an inkjet recording type image recording apparatus, when ink is continuously ejected, heat is generated by the driving energy. This heat may change the viscosity characteristics of the ink in the nozzle array. For this reason, although the nozzle row is always driven with the same drive voltage, the amount of ink ejected may change and the density of the recorded image may differ. Generally, as the ink temperature increases, the viscosity of the ink decreases, so the amount of ink discharged increases and the density of the recorded image increases. On the contrary, when the temperature of the ink is lowered, the viscosity of the ink is increased, so that the density of the recorded image tends to be reduced.

  Patent Document 1 describes an image recording apparatus capable of changing the setting of nozzle row driving conditions without lowering the throughput of recording processing even when the recording medium is a continuous sheet. Specifically, the drive condition setting change timing is calculated based on the size information of the recorded image and the conveyance information included in the job information, and the drive condition setting change is performed at the calculated timing. Is described.

JP 2009-148945 A

  However, in the conventional example, even when the image size, particularly the image size in the transport direction, is large, the drive condition cannot be obtained and set until the gap is reached, and the drive condition cannot be changed. In addition, when the driving condition is changed in the middle of the image, if the driving condition is switched at the same position for all colors, the density of all ink colors changes at that position, and the driving condition switching position is conspicuous. There was a problem.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  According to one aspect of the invention, a printing apparatus is provided. The printing apparatus intersects the conveyance direction of the recording medium, a conveyance unit that conveys the recording medium, a first nozzle row that is arranged in a direction that intersects the conveyance direction of the recording medium, and that discharges the first ink. A second nozzle row that is arranged in a direction and ejects a second ink different from the first ink, and a first nozzle row drive that drives the first nozzle row to eject the first ink A second nozzle row driving unit that drives the second nozzle row to eject the second ink, a driving condition of the first nozzle row driving unit, and the second nozzle row driving unit A driving condition changing unit that changes the driving conditions at different positions in the image formed on the recording medium among positions along the conveyance direction of the recording medium. According to this printing apparatus, the position where the driving condition of the first nozzle row in the image formed on the recording medium is changed and the density of the first ink changes, and the driving condition of the second nozzle row is changed. Since the position where the density of the second ink changes is different, the drive condition switching position is not easily noticeable.

  In the printing apparatus of the above aspect, the second nozzle row is disposed at a position different from the first nozzle row in the transport direction, and the driving condition changing unit is configured to drive the first nozzle row driving unit. The condition and the driving condition of the second nozzle array driving unit may be changed at the same timing. According to the printing apparatus of this aspect, the second nozzle row is arranged at a position different from the first nozzle row in the transport direction, so that the driving condition changing unit drives the first nozzle row driving unit. Even if the conditions and the driving conditions of the second nozzle row driving unit are changed at the same timing, the driving conditions of the first nozzle row driving unit and the driving conditions of the second nozzle row driving unit Of the positions along the transport direction, the position can be changed at a different position in the image formed on the recording medium.

  In the printing apparatus of the above aspect, the drive condition changing unit may periodically change the drive condition. If the drive condition is changed periodically, the drive condition is changed before the ink density becomes too high, so that the drive condition switching position can be made inconspicuous.

  In the printing apparatus of the above aspect, the drive condition change timing setting for setting a drive condition change timing that is a timing for changing the setting of the drive condition in the first nozzle row drive unit and the second nozzle row drive unit is further provided. And the drive condition changing unit may change the drive conditions of the first nozzle row drive unit and the second nozzle row drive unit based on the drive condition change timing. According to the printing apparatus of this aspect, the driving condition can be changed at the timing set by the driving condition change timing setting unit.

  In the printing apparatus of the above aspect, the drive condition change timing setting unit includes a nozzle interval between the nozzles of the first nozzle row and the nozzles of the second nozzle row in the transport direction, and the transport unit Based on the conveyance speed of the recording medium, an interval between the driving condition change position of the first nozzle row driving unit on the recording medium and the driving condition change position of the second nozzle row driving unit, The timing for changing the driving condition of the first nozzle row driving unit and the timing for changing the driving condition of the second nozzle row driving unit may be set to be longer than the nozzle interval. According to the printing apparatus of this aspect, even if the driving condition of the first nozzle row driving unit and the driving condition of the second nozzle row driving unit are changed at different timings, The driving condition and the driving condition of the second nozzle array driving unit can be changed at different positions in the image formed on the recording medium among the positions along the recording medium conveyance direction.

  In the printing apparatus according to the above aspect, the drive condition change timing setting unit sets the drive condition change timing of the nozzle array drive unit arranged on the downstream side in the conveyance direction of the recording medium to the upstream side in the conveyance direction of the recording medium. It may be earlier than the drive condition change timing of the arranged nozzle array drive unit. According to the printing apparatus of this aspect, the drive condition change of the nozzle row drive unit arranged on the downstream side in the conveyance direction of the recording medium is performed before the drive condition change of the nozzle row drive unit arranged on the upstream side. The drive condition change position of the nozzle row arranged on the downstream side on the recording medium and the drive condition change position of the nozzle row arranged on the upstream side can be made different.

  In the printing apparatus according to the above aspect, the drive condition change timing setting unit is a time from the change timing of the drive condition of the first nozzle row drive unit to the change timing of the drive condition of the second nozzle row drive unit. May be longer than 2X / V. According to the printing apparatus of this aspect, even if the drive condition is changed from any one of the nozzle row arranged on the upstream side and the nozzle row arranged on the downstream side, the nozzle row on the recording medium is changed. The drive condition change position can be varied.

  In the printing apparatus according to the above aspect, the printing apparatus includes an n-color nozzle row, and when the driving condition is changed a plurality of times during printing of one image, the driving condition change timing setting unit performs the first time. The time from the last drive condition change timing of the nozzle row drive section to the first drive condition change timing of the second nozzle row drive section may be longer than nX / V. According to the printing apparatus of this embodiment, the first drive condition change position and the second drive condition change position can be made different.

  The printing apparatus according to the above aspect further includes a first ink head having the first nozzle row and a temperature sensor for measuring a temperature of the second ink head having the second nozzle row, and the driving condition The change unit sets the drive condition corresponding to the head temperature acquired by the temperature sensor in the first nozzle row drive unit and the second nozzle row drive unit every time when the drive condition is changed. May be. Since the viscosity of the ink depends on the temperature, by setting a driving condition corresponding to the temperature of the head in the first nozzle row driving unit and the second nozzle row driving unit, the ink having an optimal density can be ejected. It becomes possible.

  In the printing apparatus of the above aspect, the driving condition may be a driving waveform having an amplitude that varies depending on temperature. According to the printing apparatus of this embodiment, the drive condition is a drive waveform having an amplitude that varies depending on the temperature, and the amount of ejected ink is proportional to the magnitude of the amplitude, so that a change in the density of the recorded image can be suppressed. .

  According to an aspect of the present invention, a printing method in a printing apparatus is provided. In this printing method, while transporting the recording medium, the first ink is ejected from the first nozzle array arranged in a direction intersecting the transporting direction of the recording medium to the recording medium, and the transporting direction of the recording medium A step of discharging a second ink different from the first ink onto the recording medium from a second nozzle array arranged in a direction intersecting with the first ink, and performing the printing during the execution of the printing. A step of changing a driving condition for driving one nozzle row and a driving condition for driving the second nozzle row, a change position of the driving condition for the first nozzle row, and the second The change position of the driving condition of the nozzle row is a different position of the image formed on the recording medium among the positions along the conveyance direction of the recording medium. According to this printing method, the position where the driving condition of the first nozzle row is changed to change the density of the first ink, and the driving condition of the second nozzle row is changed to change the density of the second ink. Since the changing position is different, the switching position of the driving condition is not noticeable.

  In the printing method of the above aspect, the second nozzle row of the printing apparatus is located at a position different from the first nozzle row in the transport direction, and the driving condition of the first nozzle row, The change position of the driving condition of the first nozzle row and the change position of the driving condition of the second nozzle row are changed by changing the driving condition of the second nozzle row at the same timing. It may be a different location on the medium. According to the printing method of this aspect, since the second nozzle row is arranged at a position different from the first nozzle row in the transport direction, the drive condition changing unit is the first nozzle row drive unit. Even if the driving condition and the driving condition of the second nozzle row driving unit are changed at the same timing, the driving condition of the first nozzle row driving unit and the driving condition of the second nozzle row driving unit are changed to the recording medium. The position can be changed at a different position in the image formed on the recording medium among the positions along the transport direction.

  In the printing method of the above aspect, the recording is performed based on a nozzle interval between the nozzles of the first nozzle row and the nozzles of the second nozzle row in the transport direction and the transport speed of the recording medium. The first nozzle row is arranged so that an interval between the drive condition change position of the first nozzle row on the medium and the drive condition change position of the second nozzle row is longer than the nozzle interval. The drive condition change timing and the drive condition change timing of the second nozzle array may be set. According to the printing method of this aspect, even if the driving conditions of the first nozzle row and the driving conditions of the second nozzle row are changed at different timings, the driving condition change position of the first nozzle row and the first nozzle row are changed. The drive condition change position of the second nozzle row can be changed at a different position in the image formed on the recording medium.

  The present invention can be realized in various forms. For example, in addition to a printing apparatus and a printing method, the present invention can be realized in various forms such as a driving condition changing method in the printing apparatus.

It is explanatory drawing which shows schematic structure of the printing system in 1st Embodiment. It is explanatory drawing which shows schematic structure of the printing unit of a printing apparatus. It is explanatory drawing which shows the structure of a printing part. 3 is a printing flowchart according to the first embodiment. It is explanatory drawing which shows the example of the drive condition before the change stored in 1st drive condition memory | storage part MC1, and the drive condition of the change stored in 2nd drive condition memory | storage part MC2. It is explanatory drawing which shows the application | coating state of the paper and ink in 1st Embodiment. It is explanatory drawing which shows the application | coating state of the paper at the time of the change of the drive condition of the 2nd time in 1st Embodiment. FIG. 10 is an explanatory diagram illustrating a relationship between a sheet conveyance speed change timing and a drive condition change position interval when the nozzle interval is 10 pixels. It is explanatory drawing which shows the application | coating state of the paper and ink in 2nd Embodiment. It is explanatory drawing which shows the application | coating state of a paper and an ink when the drive condition change of the 2nd time is performed in 2nd Embodiment. FIG. 10 is an explanatory diagram illustrating a relationship between a sheet conveyance speed change timing and a drive condition change position interval when the nozzle interval is 10 pixels. It is explanatory drawing which shows the application | coating state of the paper and ink in 3rd Embodiment.

First embodiment:
FIG. 1 is an explanatory diagram illustrating a schematic configuration of a printing system according to the first embodiment. The printing system 1000 includes a printing device 10 and a computer 30. The printing apparatus 10 includes a control unit 100 and a printing unit 105. The control unit 100 includes a CPU 110, a memory 120, an interface 130 (described as “I / F” in FIG. 1), and a control unit 140. The printing unit 105 includes a paper feeding unit 150, a transport unit 160, a printing unit 170, and a winding unit 180.

  The CPU 110 of the printing apparatus 10 is connected to the computer 30 via the interface 130. The CPU 110 receives print data from the computer 30 and creates raster data. The memory 120 stores print data received by the CPU 110. The control unit 140 receives an instruction from the CPU 110 and controls the printing unit 105 to execute printing.

  The computer 30 functions as an external device that sends print data and image data to the printing apparatus 10 and includes a CPU 310 and a printer driver 320. The printer driver 320 creates print data to be transmitted to the printing apparatus 10.

  FIG. 2 is an explanatory diagram showing a schematic configuration of the printing unit 105 of the printing apparatus 10. As described above, the printing unit 105 includes the paper feeding unit 150, the transport unit 160, the printing unit 170, and the winding unit 180. The sheet feeding unit 150 includes a feeding roller 152 and a relay roller 154. The feeding roller 152 winds the continuous paper 40 in a roll shape. The relay roller 154 sends the fed paper 40 to the transport unit 160. The paper 40 corresponds to the recording medium of the claims.

  The transport unit 160 includes transport roller pairs 162 and 168 and relay rollers 163, 164, 166, and 167. The conveyance roller pairs 162 and 168 include driving rollers 162a and 168a, and driven rollers 162b and 168b arranged on the opposite side with the paper 40 in between. The relay rollers 164 and 166 are disposed on both sides of the printing unit 170. The relay roller 163 is disposed between the transport roller pair 162 and the relay roller 164, and the relay roller 167 is disposed between the transport roller pair 168 and the relay roller 166. In the present embodiment, the conveyance speed of the paper 40 is V.

  The printing unit 170 includes four types of ink head groups 70 </ b> C, 70 </ b> M, 70 </ b> Y, and 70 </ b> K provided for each color, and a rotating drum 172. In the present embodiment, inks of four colors (cyan, magenta, yellow, and black) are used. Letters “C”, “M”, etc., at the end of the reference numerals attached to the ink head group are subscripts that mean colors. When there is no need to distinguish colors, the alphabetic characters are omitted and referred to as “ink head group 70”. In the present embodiment, the ink head groups 70 are arranged in the order of the ink head groups 70C, 70M, 70Y, and 70K from the upstream side. Each of the ink head groups 70C, 70M, 70Y, and 70K includes nozzle rows 72C, 72M, 72Y, and 72K7 arranged in a direction that intersects the conveyance direction of the paper 40. The nozzle spacing between the nozzle rows 72C and 72M, the nozzle spacing between the nozzle rows 72M and 72Y, and the nozzle spacing between the nozzle rows 72Y and 72L are all X, and the nozzle rows 72C, 72M, 72Y, and 72K are equally spaced. Has been placed.

  The rotating drum 172 is a member that supports the paper 40 and has a cylindrical shape in the present embodiment. The ink head group 70 is disposed along the cylindrical surface of the rotary drum 172, and the paper 40 is conveyed between the ink head group 70 and the rotary drum 172. The winding unit 180 includes a winding roller 182 and a relay roller 184. The take-up roller 182 takes up the printed paper 40. The member that supports the paper 40 is not limited to a cylindrical shape such as the rotating drum 172. For example, it is possible to use a flat platen that supports the paper 40 on a flat surface.

  The printing apparatus 10 according to the present embodiment includes a feeding roller 152 in the paper feeding unit 150 and a winding roller 182 in the winding unit 180, and is configured to print on continuous paper. However, the printing apparatus 10 may be configured to include a cut sheet supply unit instead of the feeding roller 152 and a cut sheet discharge unit instead of the winding unit 180 to print on the cut sheet. Further, the number of ink colors may be four or more.

  FIG. 3 is an explanatory diagram illustrating the configuration of the printing unit 170. The printing unit 170 includes a driving condition change timing setting unit 190, driving waveform generation units 200C, 200M, 200Y, and 200K provided for each color, ink head groups 70C, 70M, 70Y, and 70K, and temperature sensors 74C and 74M. , 74Y, 74K. The drive condition change timing setting unit 190 sets the timing for changing the drive condition, and issues a drive condition acquisition instruction and a drive condition change instruction to the drive waveform generation units 200C, 200M, 200Y, and 200K. The drive waveform generation units 200C, 200M, 200Y, and 200K change the drive condition in response to an instruction to change the drive condition, and drive the ink head groups 70C, 70M, 70Y, and 70K according to the drive condition. Since the configuration of the drive waveform generation unit is the same even when the colors are different, the configuration of the drive waveform generation unit 200C and the ink head group 70C will be described as an example by taking cyan as an example.

  The ink head group 70C has a plurality of ink heads 71C. The plurality of ink heads 71 </ b> C are arranged in a staggered manner along a direction intersecting the conveyance direction of the paper 40 to form one line head. Each ink head 71 </ b> C has a nozzle row 72 </ b> C arranged in a direction intersecting with the conveyance direction of the paper 40. The temperature sensor 74C measures the temperature of the ink head group 70C.

  The drive waveform generation unit 200C includes a reception unit 210C, a drive condition acquisition / setting unit 220C, a nozzle array drive unit 230C, a print data buffer 250C, a storage unit 260C, and a bus 270C that connects them. The receiving unit 210C receives image data from the control unit 140, and receives a drive condition change instruction from the drive condition change timing setting unit 190. The drive condition acquisition / setting unit 220C changes the drive condition for driving the nozzle row 72C. In the ink head group 70 of the ink jet printing apparatus 10, when ink is continuously ejected, heat is generated by the driving energy. This heat may change the viscosity characteristics of the ink in the nozzle row 72. For this reason, although the nozzle row 72 is always driven under the same driving conditions, the amount of ink ejected may change, and the density of the recorded image may differ. In order to suppress this, the drive condition acquisition / setting unit 220C changes the drive condition of the nozzle row 72 during printing.

  The nozzle row driving unit 230C drives the ink head group 70C according to the set driving conditions, and discharges ink from the nozzle row 72C. The print data buffer 250C temporarily stores image data sent to the nozzle row 72C. The storage unit 260C includes a first drive condition storage unit MC1 and a second drive condition storage unit MC2. The first drive condition storage unit MC1 and the second drive condition storage unit MC2 store drive conditions for driving the nozzle row 72C. The first drive condition storage unit MC1 and the second drive condition storage unit MC2 are properly used as follows. For example, first, at the time of printing, the driving condition stored in the first driving condition storage unit MC1 is set and used as the driving condition for driving the nozzle row driving unit 230C. When receiving the drive condition acquisition instruction, the drive condition to be used after the change is calculated and stored in the second drive condition storage unit MC2. When the drive condition change instruction is received, the drive condition stored in the second drive condition storage unit MC2 is set and used as the drive condition for driving the nozzle array drive unit 230C. The first drive condition storage unit MC1 is used for storing drive conditions when the next drive condition acquisition instruction is received. Thus, the first drive condition storage unit MC1 and the second drive condition storage unit MC2 alternately store the drive condition used for the current printing and the drive condition used for the changed printing.

  The first ink in the claims is any one of cyan ink, magenta ink, yellow ink, and black ink, and the second ink is any one of three color inks other than the first ink. The first nozzle row and the second nozzle row are nozzle rows that discharge the first ink and the second ink, respectively. The first nozzle row driving unit and the second nozzle row driving unit are: These are nozzle row drive units that drive the first nozzle row and the second nozzle row, respectively, and the first ink head and the second ink head respectively include the first nozzle row and the second nozzle row. Head.

  FIG. 4 is a printing flowchart according to the first embodiment. When printing is started in step S100, the nozzle row driving unit 230C drives the nozzle row 72C according to the driving conditions stored in the first driving condition storage unit MC1 to discharge ink. In step S110, when the drive waveform acquisition timing is reached, the drive condition change timing setting unit 190 proceeds to step S120, transmits a drive condition acquisition instruction to the drive condition change unit 220C, and sets the ink head group 70C. Get the temperature. In step S130, the changed drive waveform is calculated. In step S140, the changed drive waveform is stored in the second drive condition storage unit MC2. In the first embodiment, the drive condition change timing setting unit 190 transmits a drive condition acquisition instruction to the drive condition change units 220C, 220M, 220Y, and 220K for all colors at the same time.

  FIG. 5 is an explanatory diagram illustrating an example of the drive condition before change stored in the first drive condition storage unit MC1 and the drive condition after change stored in the second drive condition storage unit MC2. . In this embodiment, the driving waveform of the nozzle row is used as the driving condition. FIG. 5A is an example in which the amplitude is different between the drive waveform before the change and the drive waveform after the change. In FIG. 5B, the duty of the waveform is changed between the drive waveform before the change and the drive waveform after the change. Thus, in the present embodiment, the amount of ink ejected from the nozzle row 72C is adjusted by changing the amplitude or duty of the drive waveform. In FIG. 5A, the amplitude of the drive waveform after the change is smaller than the amplitude of the drive waveform before the change, but the drive waveform after the change depends on the temperature of the ink head group 70C before and after the change. The amplitude may be larger than the amplitude of the drive waveform before the change. The same applies to the duty ratio shown in FIG.

  In step S150 of FIG. 4, when the drive waveform change timing is reached, the drive condition change timing setting unit 190 proceeds to step S160 and transmits a drive condition change instruction to the drive condition change unit 220C. In step S170, the drive condition changing unit 220C switches the drive condition of the nozzle row 72C to the drive condition stored in the second drive condition storage unit MC2, and executes printing. In step S180, control unit 140 determines whether printing has been completed. If the printing has not been completed, the control unit 140 proceeds to step S110. Thereafter, the processing of steps S110 to S170 is repeated until printing is completed.

  FIG. 6 is an explanatory diagram showing the application state of paper and ink in the first embodiment. In this embodiment, the ink head group 70C for cyan ink is at the uppermost stream, and the magenta ink head group 70M, the yellow ink head group 70Y, and the black ink ink at the nozzle interval X toward the downstream. They are arranged in the order of the head group 70K. When the drive conditions of all the color nozzle arrays are changed simultaneously, the cyan ink drive condition change point PC1, the magenta ink drive condition change point PM1, the yellow ink drive condition change point PY1, and the black ink are changed. The drive condition change points PK1 are different positions. At the drive condition change points PC1, PM1, PY1, and PK1, since the drive condition is changed only for one color, the ink density changes only for one color. Therefore, even if the driving condition is changed in the middle of the image, the color change on the printed image is not noticeable.

  FIG. 7 is an explanatory diagram illustrating a paper and ink application state when the driving condition is changed for the second time in the first embodiment. When the drive condition is changed a plurality of times during printing of one image, the drive condition change position becomes conspicuous if the drive condition change position in the second drive condition change overlaps with the first drive condition change position. There is a fear. Of the first drive condition change positions PC1, PM1, PY1, and PK1, the position of the drive condition change position PC1 that is the most upstream of the paper and the second drive condition change position PC2, PM2, PY2, and PK2 are the most paper. The position of the drive condition change position PC1 may be located downstream of the drive condition change position PK2 with respect to the position of the drive condition change position PK2 on the downstream side of the nozzle. I just need it. For this purpose, the second drive condition change timing may be set to a time T1 or later after T1 ≧ 4X / V after the first drive condition change. When the ink color is n, since there are n nozzle rows 72, the time may be after time T1 that satisfies T1 ≧ nX / V. In addition, the drive condition change timing of each time may be periodically performed.

  As described above, according to the first embodiment, the nozzle row of a certain color is arranged at a position different from the nozzle rows of other colors in the paper transport direction, and the drive condition changing unit is configured to perform nozzle rows of all colors. Since the drive condition of the drive unit is changed at the same timing, the drive condition change position in the image printed for each color is different, so that the drive condition change position can be made inconspicuous. Note that when the drive condition change position overlaps with a blank portion (an area that is not printed, for example, a white portion), ink is not ejected at the drive condition change position, so that a density change does not appear in the image, and the drive condition change position is not conspicuous. . Therefore, when there is no blank portion, the effect of this embodiment that the drive condition change position is not conspicuous is great.

Second embodiment:
In the first embodiment, the driving conditions of the nozzle row driving units for all colors are changed at the same timing. However, in the second embodiment, the driving conditions are sequentially set from the nozzle rows of the colors arranged on the downstream side. To change. That is, the drive condition change timing of the nozzle row drive unit arranged on the downstream side is made earlier than the drive condition change timing of the nozzle row drive unit arranged on the upstream side. The configuration of the second embodiment is the same as the configuration shown in FIGS. The printing flowchart is almost the same as the flowchart shown in FIG. 4 except for the following points. In the first embodiment, in step S110, the drive condition change timing setting unit 190 transmits a drive condition acquisition instruction to the drive condition change units 220C, 220M, 220Y, and 220K for all colors at the same time. In this embodiment, a driving condition acquisition instruction is transmitted in order from the driving condition changing unit 220K for black ink arranged on the downstream side. The same applies to the drive condition change in steps S140 and S150.

  FIG. 8 is an explanatory diagram showing the relationship between the sheet conveyance speed, the change timing, and the drive condition change position interval when the nozzle interval is 10 pixels. When the nozzle row driving condition is changed from the downstream black ink nozzle row 72K, the driving condition change position interval is the nozzle row interval X (= 10 pixels) regardless of the change timing T3 and the conveyance speed V of the paper 40. Therefore, the drive conditions from the black ink nozzle row 72K to the cyan ink nozzle row 72C may be changed at any timing as long as they are performed in order.

  FIG. 9 is an explanatory diagram showing the application state of paper and ink in the second embodiment. In FIG. 9A, the drive condition of the nozzle row 72K of the black ink head group 70K on the most downstream side is changed. Next, in FIG. 9B, the driving condition of the nozzle row 72Y of the yellow ink head group 70Y is changed, and in FIG. 9C, the driving condition of the nozzle row 72M of the magenta ink head group 70M is changed. In FIG. 9D, the driving condition of the nozzle row 72C of the cyan ink head group 70C is changed. FIG. 9E shows a state where printing is performed a little after the drive conditions of the nozzle row 72C of the ink head of cyan ink are changed. The intervals of the first drive condition change positions PC3, PM3, PY3, PK3 are Lx3 and are larger than the nozzle interval X.

  FIG. 10 is an explanatory diagram showing the application state of paper and ink when the second driving condition change is performed in the second embodiment. If the first drive condition change position in the second drive condition change overlaps with the last drive condition change position in the first time, the drive condition switching position may be conspicuous. Among the first drive condition change positions PC3, PM3, PY3, and PK3, the position of the drive condition change position PC3 that is the most upstream of the paper and the second paper among the second drive condition change positions PC4, PM4, PY4, and PK4. The position of the drive condition change position PC3 may be located downstream of the drive condition change position PK4, preferably downstream of the nozzle interval X or more. I just need it. For this purpose, the second drive condition change timing of the black ink nozzle row 72K may be set to a time T4 after the change of the first drive condition of the cyan ink nozzle row 72C after T4 ≧ 4X / V. . Note that when the ink color is n, since there are n nozzle rows 72, the time may be after time T4 that satisfies T1 ≧ nX / V.

  According to the present embodiment, since the change is made from the downstream nozzle row, the drive condition change position does not overlap, and the drive condition change position on the print image can be made inconspicuous.

Third embodiment:
In the first embodiment, the driving conditions of the nozzle row driving units for all colors are changed at the same timing. However, in the third embodiment, the driving conditions are sequentially set from the nozzle row of the color arranged on the upstream side. To change.

  The configuration of the third embodiment is the same as the configuration shown in FIGS. The printing flowchart is almost the same as the flowchart shown in FIG. 4 except for the following points. In the first embodiment, in step S110, the drive condition change timing setting unit 190 transmits a drive condition acquisition instruction to the drive condition change units 220C, 220M, 220Y, and 220K for all colors at the same time. In this embodiment, a drive condition acquisition instruction is sequentially transmitted from the cyan ink drive condition changing unit 220C arranged on the upstream side. The same applies to the drive condition change in steps S140 and S150.

  FIG. 11 is an explanatory diagram showing the relationship between the sheet conveyance speed, the change timing, and the drive condition change position interval when the nozzle interval is 10 pixels. When the drive condition of the nozzle row is changed from the upstream cyan ink nozzle row 72K, the interval between the drive condition change positions is once narrowed as the change timing is lengthened and then widened. Specifically, while the drive condition change position is on the upstream side of the nozzle row to be changed next, as the change timing becomes longer, the interval between the drive condition change positions becomes narrower, and the drive condition change position becomes In the case where it is located downstream of the nozzle row to be changed next, the interval between the drive condition change positions increases as the change timing becomes longer. If the change timing T5 is 2X / V or more, the drive condition change position is located X or more downstream from the nozzle row to be changed next, so the drive conditions of the nozzle rows of all colors are changed simultaneously. Rather than the drive condition change position interval.

  FIG. 12 is an explanatory diagram showing the application state of paper and ink in the third embodiment. FIG. 12A shows a state when the drive condition of the cyan ink nozzle row 72C is changed, and FIG. 12B shows a state when the drive condition of the magenta ink nozzle row 72M is changed. If the timing T5 from the change of the drive condition of the cyan ink nozzle row 72C to the change of the drive condition of the magenta ink nozzle row 72M is 2X / V or more, the cyan ink drive condition change position PC5 and the magenta ink drive condition The distance Lx5 between the change position PM5 and the nozzle position X is equal to or greater than the nozzle position X. Timing from changing the driving condition of the magenta ink nozzle row 72M to changing the driving condition of the yellow ink nozzle row 72Y, and timing from changing the driving condition of the yellow ink nozzle row 72Y to changing the driving condition of the black ink nozzle row 72K Is the same. The change in the drive condition for the second black ink nozzle row 72C from the change in the drive condition for the first black ink nozzle row 72K is the same as the change in the nozzle row from the downstream side to the upstream side. It may be timing.

  As described above, when the driving conditions are changed in order from the color nozzle row arranged on the upstream side, the driving condition change timing may be set to 2X / V or more.

  In the printing apparatus of the above embodiment, the storage unit 260C includes the first drive waveform storage unit MC1 and the second drive waveform storage unit MC2 and is configured to alternately switch between them, but the drive waveform corresponding to each temperature And a drive waveform may be selected according to the temperature of the nozzle row 72C at the drive condition calculation start position. The drive waveform is a waveform whose amplitude varies depending on the temperature. For example, when the temperature is high, the viscosity of the drive waveform may be small because the viscosity of the ink is low.

  In the above embodiment, a driving waveform having a different amplitude depending on the temperature is used as the driving condition, but other driving conditions may be used. For example, a drive waveform in which the duty ratio of the drive waveform and the cycle of the drive waveform are changed may be used.

  The embodiments of the present invention have been described above based on some examples. However, the above-described embodiments of the present invention are for facilitating the understanding of the present invention and limit the present invention. It is not a thing. The present invention can be changed and improved without departing from the spirit and scope of the claims, and it is needless to say that the present invention includes equivalents thereof.

    DESCRIPTION OF SYMBOLS 10 ... Printing apparatus 30 ... Computer 40 ... Paper 70, 70C, 70M, 70Y, 70K ... Ink head group 71C, 71M, 71Y, 71K ... Ink head 72C, 72M, 72Y, 72K ... Nozzle row 74C ... Temperature sensor 100 ... Control Unit 105 ... Printing unit 110 ... CPU 120 ... Memory 130 ... Interface 140 ... Control unit 150 ... Paper feeding unit 152 ... Feeding roller 154 ... Relay roller 160 ... Conveying unit 162 ... Conveying roller pair 162a ... Drive roller 162b ... Driving roller 163, 164, 166, 167 ... Relay roller 168 ... Conveying roller pair 170 ... Printing unit 172 ... Rotating drum 180 ... Winding unit 182 ... Winding roller 184 ... Relay roller 90 ... Drive condition change timing setting unit 200C ... Drive waveform generation unit 210C ... Reception unit 220C ... Drive condition acquisition / setting unit 230C, 230M, 230Y, 230K ... Nozzle array drive unit 240C ... Counter 250C ... Print data buffer 260C ... Storage unit 270C ... Bus 310 ... CPU 320 ... Printer driver 1000 ... Printing system

Claims (13)

A transport unit for transporting the recording medium;
A first nozzle row that is disposed in a direction crossing the transport direction of the recording medium and that discharges the first ink;
A second nozzle array that is disposed in a direction intersecting the conveyance direction of the recording medium and that ejects a second ink different from the first ink;
A first nozzle row driving section for driving the first nozzle row and discharging the first ink;
A second nozzle row driving section for driving the second nozzle row and discharging the second ink;
The driving conditions of the first nozzle row driving unit and the driving conditions of the second nozzle row driving unit are different positions in the image formed on the recording medium among the positions along the conveyance direction of the recording medium. A drive condition change unit to be changed in
A printing apparatus comprising: The printing apparatus according to claim 1,
The second nozzle row is disposed at a position different from the first nozzle row in the transport direction,
The driving condition changing unit is a printing apparatus that changes the driving condition of the first nozzle row driving unit and the driving condition of the second nozzle row driving unit at the same timing. The printing apparatus according to claim 1 or 2,
The driving condition changing unit is a printing apparatus that periodically changes the driving condition. In the printing apparatus as described in any one of Claims 1-3, Furthermore,
A drive condition change timing setting unit for setting a drive condition change timing that is a timing for changing the setting of the drive condition in the first nozzle row drive unit and the second nozzle row drive unit;
The drive condition change unit is a printing apparatus that changes the drive conditions of the first nozzle row drive unit and the second nozzle row drive unit based on the drive condition change timing. The printing apparatus according to claim 4,
The drive condition change timing setting unit includes a nozzle interval between the nozzles of the first nozzle row and the nozzles of the second nozzle row in the transport direction, a transport speed of the recording medium by the transport unit, Based on the above, the interval between the drive condition change position of the first nozzle row drive unit on the recording medium and the drive condition change position of the second nozzle row drive unit is made longer than the nozzle interval. As described above, the printing apparatus sets the timing for changing the driving condition of the first nozzle row driving unit and the timing for changing the driving condition of the second nozzle row driving unit. The printing apparatus according to claim 5, wherein
The drive condition change timing setting unit sets a drive condition change timing of a nozzle row drive unit arranged on the downstream side in the conveyance direction of the recording medium, and a nozzle row drive unit arranged on the upstream side in the conveyance direction of the recording medium Printing device that is earlier than the drive condition change timing. The printing apparatus according to claim 5 or 6,
The drive condition change timing setting unit sets a time period from the drive condition change timing of the first nozzle row drive unit to the drive condition change timing of the second nozzle row drive unit longer than 2X / V. A printing device. In the printing device according to claim 4-7,
The printing apparatus includes an n-color nozzle row,
When the drive condition is changed a plurality of times during printing of one image, the drive condition change timing setting unit performs the second nozzle row from the last drive condition change timing of the first nozzle row drive unit. A printing apparatus in which the time until the first drive condition change timing of the drive unit is made longer than nX / V. The printing apparatus according to claim 1,
And a temperature sensor for measuring the temperature of the first ink head having the first nozzle row and the second ink head having the second nozzle row,
The driving condition changing unit changes the driving condition corresponding to the temperature of the head acquired by the temperature sensor every time when the driving condition is changed, to the first nozzle row driving unit and the second nozzle row driving unit. Set to the printing device. The printing apparatus according to claim 1,
The printing apparatus, wherein the driving condition is a driving waveform whose amplitude varies depending on temperature. A printing method in a printing apparatus,
While transporting the recording medium, the first ink is ejected from the first nozzle array arranged in a direction intersecting the transport direction of the recording medium to the recording medium, and in a direction intersecting the transport direction of the recording medium. A step of performing printing by discharging a second ink different from the first ink onto the recording medium from the arranged second nozzle row;
Changing a driving condition for driving the first nozzle row and a driving condition for driving the second nozzle row during execution of the printing;
With
The change position of the driving condition of the first nozzle row and the change position of the driving condition of the second nozzle row are positions of the image formed on the recording medium among positions along the conveyance direction of the recording medium. A printing method that is in a different position. The printing method according to claim 11, wherein
The second nozzle row of the printing apparatus is located at a position different from the first nozzle row in the transport direction;
By changing the driving condition of the first nozzle row and the driving condition of the second nozzle row at the same timing, the change position of the driving condition of the first nozzle row and the second nozzle The printing method, wherein the change position of the driving condition of the row is a different position of the recording medium. In the printing method according to claim 11, based on the nozzle interval between the nozzles of the first nozzle row and the nozzles of the second nozzle row in the transport direction, and the transport speed of the recording medium, The first nozzle so that the interval between the drive condition change position of the first nozzle row on the recording medium and the drive condition change position of the second nozzle row is longer than the nozzle interval. The printing method of setting the change timing of the drive condition of the row and the change timing of the drive condition of the second nozzle row.

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