JP2020082667A - Transmission data preparation device and inkjet printer - Google Patents

Abstract

To suppress an increase in a level of radiation noise when transmission data is transmitted to an ink head.SOLUTION: A transmission data preparation device 60 is a device which prepares transmission printing image data PD2 transmitted to an ink head 40 and a transmission clock CS2. In the transmission data preparation device 60, a clock preparation part 73 for time division prepares a clock CS10 for time division with a higher frequency than that of an internal clock CS20. A dime division part 75 divides a reference clock CS1 on the basis of the clock CS10 for time division. A transmission clock preparation part 77 selects at least one division clock from the individual divided division clocks and deletes the selected division clocks, and thereby prepares a transmission clock CS2. A printing image data creation part 78 adjusts a rate of reference printing image data PD1 so as to correspond to the transmission clock CS2, and thereby prepares the transmission printing image data PD2.SELECTED DRAWING: Figure 7

Description

The present invention relates to a transmission data creation device and an inkjet printer. More specifically, the present invention relates to a transmission data creation device that creates transmission data that is transmitted to an ink head and that has a clock and print image data corresponding to the clock, and an inkjet printer that includes the transmission data creation device.

Conventionally, an inkjet printer provided with a support such as a platen for supporting a recording medium, an ink head for ejecting ink toward the recording medium, and a control device electrically connected to the ink head via a cable. It has been known. In this type of inkjet printer, transmission data is transmitted from the control device to the ink head. The transmission data includes, for example, a clock (in other words, a clock signal) and print image data obtained by converting a print image to be printed into raster data.

When this transmission data is transmitted to the ink head, a high current flows through the cable connecting the ink head and the control device. As a result, when the cable acts as an antenna, radiation noise may be generated from the cable. This radiated noise causes a malfunction in peripheral devices.

Therefore, in order to suppress the generation of radiation noise, for example, in Japanese Patent Application Laid-Open No. 2004-242242, a nozzle row formed by a plurality of nozzles provided in each of a plurality of ink heads is divided into a plurality of groups, and each divided group is divided into groups. A recording device for generating clocks having different frequencies is disclosed. This makes it possible to suppress an increase in the level of radiation noise.

JP, 2008-279616, A

However, in the recording device disclosed in Patent Document 1, a specific frequency exists for each divided group. Therefore, radiation noise remarkably occurs in a specific frequency range in each group.

The present invention has been made in view of the above points, and an object thereof is to create transmission data capable of suppressing an increase in the level of radiation noise generated when transmitting transmission data to an ink head. A transmission data creating device and an inkjet printer are provided.

A transmission data creating apparatus according to the present invention is a printer having an ink head for ejecting ink, and is transmission print image data which is print image data transmitted to the ink head and a clock transmitted to the ink head. A transmission data creation device for creating transmission data having a transmission clock. The transmission data creation device includes a storage unit, an internal clock, a time-division clock creation unit, a time-division unit, a transmission clock creation unit, and a print image data creation unit. The storage unit stores a reference clock that is a clock having a plurality of pulses with the same period, and reference print image data that is print image data corresponding to the reference clock. In the internal clock, the frequency is a predetermined internal frequency. The time-division clock creation unit creates a time-division clock whose frequency is a predetermined first frequency higher than the internal frequency of the internal clock, based on the internal clock. The time division unit is based on a half cycle corresponding to the first frequency of the time division clock, and is the half cycle, or a half cycle of the full cycle when the half cycle is a full cycle. The reference clock is divided into a plurality of divided clocks by dividing the reference clock at intervals of a half cycle. The transmission clock creation unit, when one divided clock selected from the plurality of divided clocks is the first selected divided clock, sets the reference clock after deleting the first selected divided clock as the transmission clock. .. The print image data creation unit creates the transmission print image data by adjusting the data rate of the reference print image data so as to correspond to the transmission clock created by the transmission clock creation unit.

According to the transmission data creation device, the first frequency of the time division clock is higher than the internal frequency of the internal clock. When the reference clock is divided by the time division unit, the reference clock is divided at intervals of a half cycle corresponding to the first frequency of the time division clock, or the entire circumference half cycle. The half cycle or the full circumference half cycle corresponding to the first frequency becomes shorter as the frequency becomes higher. Therefore, the shorter the interval of the half cycle or the full circumference half cycle becomes, the smaller the number of divisions of the reference clock becomes. Can be a lot. In addition, in the transmission data creation device, by deleting the divided clock selected from the plurality of divided clocks, the cycle of the pulse to which the deleted divided clock belongs is shortened. Therefore, it is easy to make the cycles of the pulses different. In the transmission data creation device, for example, when dividing the reference clock, the number of divided clocks is larger than that when the internal clock is used. Therefore, there are many choices of the divided clocks that can be deleted, and the pulse cycle can be set to various numerical values, so that the pulse cycle is more likely to be different. Therefore, it is easy to create a transmission clock that does not have a specific frequency, and it is possible to prevent the level of radiation noise from increasing at a specific frequency. Therefore, it is possible to create a transmission clock capable of suppressing an increase in the level of radiation noise generated.

According to the present invention, it is possible to create transmission data that can suppress an increase in the level of radiation noise that occurs when transmitting transmission data to an ink head.

FIG. 3 is a perspective view showing the inkjet printer according to the first embodiment. FIG. 3 is a plan view showing the internal configuration of the inkjet printer. FIG. 6 is a bottom view of the ink head. It is a block diagram of an inkjet printer. 6 is a time chart of reference print image data and a reference clock. It is a block diagram of a phase synchronization circuit. 7 is a time chart of transmission print image data and a transmission clock. 7 is a flowchart showing a procedure for creating transmission data. It is a time chart which shows an internal clock and a clock for time division. 6 is a time chart of reference print image data and a reference clock showing a state of time division. 7 is a time chart showing an internal clock and first to fourth time division clocks according to the second embodiment.

Hereinafter, an inkjet printer according to an embodiment of the present invention (hereinafter, simply referred to as “printer”) will be described with reference to the drawings. It should be noted that the embodiments described here are not, of course, intended to limit the present invention. In addition, the same reference numerals are given to members and parts that have the same action, and duplicate description will be appropriately omitted or simplified.

<First Embodiment>
FIG. 1 is a perspective view of the printer 100 according to the first embodiment. In the following description, front, rear, left, right, upper, and lower mean front, rear, left, right, upper, and lower, respectively, when the printer 100 is viewed from the front. The symbols F, Rr, L, R, U, and D in the drawings mean front, rear, left, right, upper, and lower, respectively. However, the above direction is only a direction determined for convenience of description, and does not limit the installation mode of the printer 100. Reference numeral Y in the drawing indicates the main scanning direction. Here, the main scanning direction Y is the left-right direction. The symbol X indicates the sub-scanning direction. Here, the sub-scanning direction X is the front-back direction and is orthogonal to the main scanning direction Y in plan view. However, the main scanning direction Y and the sub scanning direction X are not particularly limited, and can be set appropriately according to the form of the printer 100.

As shown in FIG. 1, the printer 100 is an inkjet printer. The printer 100 prints on the recording medium 5. Here, the recording medium 5 is a roll-shaped recording paper. However, the recording medium 5 may be a sheet-shaped recording paper or a resin sheet. The recording medium 5 is not limited to a flexible sheet, and may be a medium made of a hard material such as a glass substrate.

In this embodiment, the printer 100 includes a main body 10 having a casing, legs 11 provided at the bottom of the main body 10 to support the main body 10, an operation panel 12 for a user to perform printing-related operations, and an upper portion of the main body 10. The cover 15 is provided on the. Below the cover 15 and on the front side of the main body 10, a discharge port 13 for discharging the recording medium 5 is formed. A guide 14 for guiding the recording medium 5 discharged from the discharge port 13 is provided at a position in front of and below the discharge port 13.

FIG. 2 is a plan view showing the internal configuration of the printer 100. FIG. 3 is a bottom view of the ink head 40. FIG. 4 is a block diagram of the printer 100. As shown in FIG. 2, the printer 100 includes a guide rail 20, a platen 25, a first moving mechanism 51, a second moving mechanism 52, a carriage 30, an ink head 40 (see FIG. 3), and a controller. 55 (see FIG. 4) and a transmission data creation device 60 (see FIG. 4). The guide rail 20 is arranged below the cover 15 (see FIG. 1). The guide rail 20 extends in the main scanning direction Y.

The platen 25 supports the recording medium 5 when printing on the recording medium 5. The recording medium 5 is placed on the platen 25. Printing on the recording medium 5 is performed on the platen 25. In the present embodiment, the platen 25 extends in the main scanning direction Y and is arranged below the central portion of the guide rail 20. The platen 25 is connected to the guide 14 (see FIG. 1).

In the present embodiment, the length of the platen 25 in the main scanning direction Y (here, the left-right direction) is 20 inches or more. For example, the length of the platen 25 in the main scanning direction Y is equal to or greater than the lateral width of the A0 size sheet (in other words, the length of the short side). Here, the A0 size paper has a size of 841 mm×1189 mm, and the width of the A0 size paper is 841 mm. The length of the platen 25 in the main scanning direction Y is equal to or greater than the vertical width of the A1 size sheet (in other words, the length of the long side). The length of the platen 25 in the main scanning direction Y is equal to or larger than the width of the B1 size sheet. In the present embodiment, the length of the main body 10 of the printer 100 in the main scanning direction Y is longer than the length of one arm of the user. The length of the main body 10 in the main scanning direction Y is longer than the length from the user's eyes to the fingertip of one arm when the user extends one arm in the main scanning direction Y. The printer 100 is a so-called large-sized printer, which is longer than the home printer in the main scanning direction Y as compared with the home printer. The printer 100 is a commercial printer.

The first moving mechanism 51 is a mechanism that moves the recording medium 5 supported by the platen 25 in the sub-scanning direction X with respect to the ink head 40 (see FIG. 3). In the present embodiment, the first moving mechanism 51 includes a pair of upper and lower rollers 26 (hereinafter, referred to as a pair of rollers 26) and a motor 27. Note that, in the pair of rollers 26, the upper roller 26 is illustrated in FIG. 2, and the lower roller 26 is omitted. The number and installation position of the pair of rollers 26 are not particularly limited. Here, one roller 26 of the pair of rollers 26 is a grit roller. A motor 27 is connected to the grid roller 26. The grit roller 26 is rotated by driving the motor 27. The other roller 26 of the pair of rollers 26 is a pinch roller for sandwiching the recording medium 5 together with the grit roller. The recording medium 5 is conveyed in the sub-scanning direction X by driving the motor 27 while the recording medium 5 is sandwiched by the pair of rollers 26.

The second moving mechanism 52 is a mechanism that moves the ink head 40 (see FIG. 3) in the main scanning direction Y with respect to the recording medium 5 supported by the platen 25. In the present embodiment, the second moving mechanism 52 has a pulley 21, a pulley 22, a belt 23, and a motor 24. The pulley 21 is provided at the right end portion of the guide rail 20, and the pulley 22 is provided at the left end portion of the guide rail 20. The belt 23 is endless and is wound around the pulley 21 and the pulley 22. The belt 23 may have a structure in which both ends are fixed to the pulleys 21 and 22 instead of being endless. The motor 24 is connected to the pulley 21, for example. By driving the pulley 21 with the driving of the motor 24, the belt 23 runs between the pulley 21 and the pulley 22. The second moving mechanism 52 may not include the pulley 21, the pulley 22, and the belt 23. For example, the second moving mechanism 52 may include a shaft, a first gear provided on the shaft, a second gear that meshes with the first gear, and the like. In this case, the motor 24 is connected to the shaft, and the first gear and the second gear rotate as the motor 24 is driven.

In the present embodiment, the carriage 30 is attached to the belt 23. Although illustration is omitted, the carriage 30 is engaged with the guide rail 20. The carriage 30 moves in the main scanning direction Y along the guide rails 20 as the belt 23 travels by the second moving mechanism 52.

The ink head 40 ejects ink toward the recording medium 5 placed on the platen 25. As shown in FIG. 3, the ink head 40 is mounted on the carriage 30. The ink head 40 is arranged above the platen 25 (see FIG. 2) and slidably engages with the guide rail 20 (see FIG. 2) via the carriage 30. The ink head 40 moves in the main scanning direction Y along the guide rail 20 by the second moving mechanism 52. The number of ink heads 40 is not particularly limited. In this embodiment, the number of ink heads 40 is four. The four ink heads 40 are arranged side by side in the main scanning direction Y. Here, the four ink heads 40 are referred to from the left as a first ink head 41, a second ink head 42, a third ink head 43, and a fourth ink head 44. Inks of different colors are ejected from the four ink heads 40. For example, ink of any one of cyan, magenta, yellow, and black is ejected from each of the four ink heads 40. A plurality of nozzles 46 aligned in the sub-scanning direction X are formed on the bottom surface of each ink head 40. Ink is ejected from the plurality of nozzles 46.

In this embodiment, an ink cartridge 45 (see FIG. 2) is connected to the ink head 40. Here, the ink head 40 and the ink cartridge 45 are connected to each other via a tube 46 (see FIG. 2). The ink cartridge 45 contains ink to be supplied to the ink head 40, that is, ink used for printing. The installation position of the ink cartridge 45 is not particularly limited. For example, although not shown, the ink cartridge 45 is detachably provided on the upper surface of the main body 10. Although illustration is omitted, a pump for controlling pressure, a damper, and the like may be provided between the ink cartridge 45 and the ink head 40.

Next, the control device 55 will be described. As shown in FIG. 4, the control device 55 is a device that controls printing. The control device 55 is composed of a microcomputer and is provided inside the main body 10. The control device 55 includes a central processing unit (CPU), a ROM that stores programs executed by the CPU, a RAM, and the like. Here, control relating to printing is performed using a program stored in the microcomputer.

In the present embodiment, the control device 55 is electrically connected to the operation panel 12, the motor 27 of the first moving mechanism 51, the motor 24 of the second moving mechanism 52, and the ink head 40. , The motor 27, the motor 24, and the ink head 40, respectively. The control device 55 receives information regarding printing from the operation panel 12. The controller 55 controls the drive of the motor 27 of the first moving mechanism 51 to control the rotation of the grit roller 26. As a result, the controller 55 controls the movement of the recording medium 5 supported by the platen 25 in the sub-scanning direction X. The controller 55 controls the drive of the motor 24 of the second moving mechanism 52 to control the rotation of the pulley 21 and the traveling of the belt 23 (see FIG. 2). As a result, the control device 55 controls the movement of the ink head 40 in the main scanning direction Y. The controller 55 controls the timing of ejecting ink from the ink head 40.

In this embodiment, the control device 55 includes a transmission unit 56. The transmission unit 56 transmits a transmission clock CS2 (see FIG. 7) described later and transmission print image data PD2 (see FIG. 7) to the ink head 40.

In the printer 100 according to this embodiment, print image data and a clock (in other words, a clock signal) are transmitted to the ink head 40. The print image data is a print image to be printed, and is data obtained by converting a print image prepared in advance into a format to be transmitted to the ink head 40. The print image data is, for example, raster data. The clock is a signal associated with the print image data. The clock defines the timing of ejecting ink from the nozzles 41 of the ink head 40. In this embodiment, the print image data and the clock are collectively referred to as transmission data. Although not shown, the ink head 40 includes a piezoelectric element that converts the electric energy applied to the ink head 40 into pressure. The structure of this piezoelectric element is not particularly limited. In the present embodiment, electric energy is applied to the ink head 40 by transmitting the print image data and the clock to the ink head 40. In the ink head 40, the applied electric energy is appropriately changed, and the piezoelectric element expands and contracts, so that the pressure converted from the electric energy changes. In the ink head 40, ink is ejected from the nozzle 46 (see FIG. 3) based on the displacement caused by the expansion and contraction of the piezoelectric element.

FIG. 5 is a time chart of the print image data PD1 and the clock CS1. As shown in FIG. 5, the clock CS1 is for a plurality of pulses _{P 1,} P 2, · · ·, is _{P n} are continuous, multiple pulses _{P 1,} P 2, · · ·, _{P n} have. In FIG. 5, the pulse periods D ₁₁ , D ₁₂ ,... D _1n , which are the periods of the respective pulses P ₁ , P ₂ ,..., P _n , are the same.

By the way, as shown in FIG. 4, the control device 55 and the ink head 40 are connected to each other by a cable 53 such as a flexible cable. The print image data PD1 and the clock CS1 are transmitted to the ink head 40 via the cable 53. When the print image data PD1 and the clock CS1 are transmitted, a current flows through the cable 53. As a result, when the cable 53 acts as an antenna, radiation noise may be generated from the cable 53. Conventionally, the clock CS1 shown in FIG. 5, as described above, each pulse _{P 1,} P 2, · · ·, pulse period _{D 11,} D 12 of _{P n,} · · _{·, D 1n} respectively the same Therefore, the clock CS1 has a specific frequency. Therefore, when the print image data PD1 and the clock CS1 as shown in FIG. 5 are transmitted to the ink head 40, radiation noise is remarkably generated in a specific frequency range. This radiated noise may cause a malfunction in devices around the printer 100. Therefore, in the present embodiment, the transmission data creation device 60 creates transmission data (specifically, print image data and clock) that suppresses the generation of radiation noise.

Next, the transmission data creation device 60 will be described. As shown in FIG. 4, the transmission data creation device 60 is provided in the printer 100. The transmission data creation device 60 is a device that creates transmission data having print image data and a clock. Here, the transmission data creation device 60 is composed of a microcomputer and is provided inside the main body 10. In this case, the transmission data creation device 60 and the control device 55 may be realized by the same microcomputer. When the transmission data creation device 60 is provided inside the main body 10, for example, the transmission data creation device 60 is incorporated in the control device 55. The transmission data creating device 60 may be provided in a personal computer. The transmission data creation device 60 includes a central processing unit (CPU), a ROM that stores programs executed by the CPU, a RAM, and the like. Here, the transmission data is created using the program stored in the microcomputer.

In the present embodiment, the transmission data creation device 60 is electrically connected to the control device 55. For example, when the transmission data creation device 60 is provided inside the main body 10, the transmission data creation device 60 functions as a part of the control device 55. In this way, the case where the transmission data creation device 60 functions as a part of the control device 55 is also included in the case where “the transmission data creation device 60 is electrically connected to the control device 55”. .. The transmission data creation device 60 creates print image data and a clock, and transmits the created print image data and the created clock to the control device 55. When the transmission data creation device 60 is provided in the personal computer, the print image data may be created by the personal computer and the clock may be created by the control device 55.

In the present embodiment, the transmission data creation device 60 includes an internal clock CS 20, a phase synchronization circuit 65, a storage unit 70, a reference print image data creation unit 71, a time division clock creation unit 73, and a time division unit 75. A transmission clock generation unit 77, a transmission print image data generation unit 78, and a transmission unit 79. The transmission print image data creation unit 78 is an example of the print image data creation unit of the present invention. Each unit of the transmission data creation device 60 may be configured by software or hardware. For example, each unit of the transmission data creation device 60 may be implemented by a processor or may be incorporated in a circuit.

The internal clock CS20 is a clock of a microcomputer or a programmable gate array, and is a clock that serves as a control reference. The internal clock CS20 is, for example, a system clock. Control related to printing is performed based on the internal clock CS20. In the present embodiment, the frequency of the internal clock CS20 is the predetermined internal frequency F20 (see FIG. 9). The internal frequency F20 is a frequency preset for each microcomputer or programmable gate array. The specific value of the internal frequency F20 is not particularly limited. For example, the internal frequency F20 is 50 MHz.

FIG. 6 is a block diagram showing the configuration of the phase synchronization circuit 65. The phase locked loop 65 is a phase locked loop and is abbreviated as PLL. The phase synchronization circuit 65 is an electronic circuit that performs feedback control based on an input periodic signal and outputs a signal whose phase is synchronized from an oscillator. In the present embodiment, the phase synchronization circuit 65 performs feedback control based on the signal of the internal clock CS20 to create a time division clock CS10 (see FIG. 9) described later. The configuration of the phase synchronization circuit 65 is not particularly limited, and the configuration of the conventional phase synchronization circuit can be adopted. As shown in FIG. 6, for example, the phase synchronization circuit 65 has a phase comparator (PFD: Phase Frequency Detector) 65a, a loop filter 65b, an oscillator 65c, and a frequency divider 65d.

The phase comparator 65a is a circuit that receives the internal clock CS20 and another signal (for example, the signal from the frequency divider 65d) as input signals, converts the mutual phase difference into a voltage, and outputs the voltage. The loop filter 65b is, for example, a low-pass filter, and blocks unnecessary short-cycle fluctuations. The loop filter 65b is connected to the phase comparator 65a. The oscillator 65c is, for example, a voltage controlled oscillator (VCO: Voltage Controlled Oscillator), and is a circuit that controls the output frequency by the voltage output from the phase comparator 65a. In the present embodiment, the output frequency output by the oscillator 65c becomes the frequency of the time division clock CS10. The oscillator 65c is connected to the loop filter 65b. The frequency divider 65d divides the output frequency output from the oscillator 65c into a fraction of an integer and outputs the result. The frequency divider 65d is connected to the oscillator 65c and the phase comparator 65a.

FIG. 7 is a time chart of the print image data PD2 transmitted to the ink head 40 and the clock CS2. FIG. 8 is a flowchart showing a procedure for creating transmission data according to this embodiment. Next, a procedure for creating the print image data PD2 and the clock CS2 as shown in FIG. 7 will be described with reference to the flowchart of FIG.

In the following description, the print image data PD2 transmitted to the ink head 40 is referred to as “transmission print image data”, and the clock CS2 transmitted to the ink head 40 is referred to as “transmission clock”. In the present embodiment, as shown in FIG. 7, the transmission clock CS2 is pulse _{P 1,} P 2, · · ·, at least a portion of the pulse period _D 21 of _{P n, D 22, ···,} D 2n Are different. For example, in the transmission clock CS2 of FIG. 7, the pulse period D _2n is different from the pulse periods D ₂₁ and D ₂₂ . In the present embodiment, the pulse cycle (in other words, frequency) of the transmission clock CS2 transmitted to the ink head 40 changes randomly. In other words, the frequency of the transmission clock CS2 has no periodicity.

Here, the transmission clock CS2 and the transmission print image data PD2 are created from the clock CS1 and the print image data PD1 of FIG. 5, respectively. Hereinafter, the clock CS1 that serves as a reference when creating the transmission clock CS2 is referred to as a “reference clock”. In addition, the print image data PD1 that serves as a reference when creating the transmission print image data PD2 is referred to as “reference print image data”.

In this embodiment, four ink heads 40 (specifically, the first to fourth ink heads 41 to 44) are provided, but the transmission clock CS2 and the transmission print image are provided for each of the four ink heads 40. The data PD2 is transmitted. The procedure for creating the transmission clock CS2 and the transmission print image data PD2 transmitted to each of the four ink heads 40 is the same. Therefore, in the following description, the transmission clock CS2 and the transmission print image data PD2 transmitted to one of the four ink heads 40 will be described.

In the present embodiment, the reference clock CS1 having a specific frequency (specifically, the frequency of the reference clock CS1) is stored in the storage unit 70 before the transmission clock CS2 and the transmission print image data PD2 are created (see FIG. 5). , And a print image (not shown) that is an image to be printed is stored in advance. The frequency of the reference clock CS1 is a frequency common to the four ink heads 40. A different reference clock CS1 may be provided for each ink head 40, or a common reference clock CS1 may be provided.

First, in step S101 of FIG. 8, the user issues a print instruction. For example, when the user operates a print start button (not shown) displayed on the operation panel 12 (see FIG. 1), a print job is transmitted from the operation panel 12 to the control device 55. Then, the control device 55 recognizes that the print instruction has been issued by receiving the print job. At this time, the control device 55 sends an instruction signal for making the transmission data creation device 60 to create the transmission data. Upon receiving the instruction signal, the transmission data creation device 60 starts creation of the transmission clock CS2 and the transmission print image data PD2, which are transmission data.

Next, in step S103 of FIG. 8, the reference print image data creation unit 71 creates the reference print image data PD1 as shown in FIG. Here, the reference print image data creation unit 71 creates the reference print image data PD1 from the print images stored in the storage unit 70. The reference print image data PD1 is data optimized for sending the raster data to the ink head 40. The reference print image data PD1 is data serving as a reference for creating the transmission print image data PD2 (see FIG. 7) transmitted to the ink head 40. The reference print image data PD1 created in step S103 is associated with the reference clock CS1 having a specific frequency as shown in FIG. In step S103, the created reference print image data PD1 is stored in the storage unit 70.

FIG. 9 is a time chart showing the internal clock CS20 and the time division clock CS10. Next, in step S105 of FIG. 8, the time division clock creation unit 73 creates the time division clock CS10 (see FIG. 9) used when creating the transmission clock CS2 and the transmission print image data PD2. In this embodiment, the time division clock CS10 is created based on the internal clock CS20. The time division clock generation unit 73 uses the internal clock CS20 as an input signal and uses the phase synchronization circuit 65 (see FIG. 6) to generate the time division clock CS10.

In the present embodiment, as shown in FIG. 9, the internal clock CS20 has a plurality of pulses PL20. The time division clock CS10 has a plurality of pulses PL10. As described above, the frequency of the internal clock CS20 is the predetermined internal frequency F20. The frequency of the time division clock CS10 is a predetermined time division frequency F10. The time division frequency F10 is an example of the first frequency of the present invention. The time division frequency F10 is a frequency higher than the internal frequency F20. Here, the time division frequency F10 is, for example, a value between 1.5 times and 5 times the internal frequency F20. For example, the internal frequency F20 is 50 MHz. For example, the time division frequency F10 is 100 MHz or 200 MHz. Therefore, the pulse period PC10 of the pulse PL10 of the time division clock CS10 is shorter than the pulse period PC20 of the pulse PL20 of the internal clock CS20. The pulse cycle PC10 is a cycle corresponding to the time division frequency F10 and is represented by the reciprocal of the time division frequency F10. Here, a half cycle of the pulse cycle PC10 of the time division clock CS10, that is, a cycle from the rising edge to the falling edge of the pulse PL10 and a cycle from the falling edge to the rising edge of the pulse PL10 are referred to as a half cycle PC10a. .

Next, in step S107 of FIG. 8, the time division unit 75 performs time division on the reference clock CS1 (see FIG. 5) and the reference print image data PD1 (see FIG. 5) associated with the reference clock CS1. .. FIG. 10 is a time chart of the reference print image data PD1 and the reference clock CS1 showing the state of time division. In the present embodiment, as shown in FIG. 10, the time division unit 75 has the reference clock CS1 at the intervals of the half cycle PC10a (hereinafter, also simply referred to as the interval PC10a) corresponding to the time division frequency F10 of the time division clock CS10. The reference print image data PD1 is divided. Here, the time division unit 75 divides the reference clock CS1 and the reference print image data PD1 at the rising timing of the pulse PL10 of the time division clock CS10 and the falling timing of the pulse PL10.

In the present embodiment, the time division unit 75 divides the reference clock CS1 and the reference print image data PD1 at intervals of the half cycle PC10a corresponding to the time division frequency F10 of the time division clock CS10 as described above. .. However, the time division unit 75 may divide the reference clock CS1 at intervals of a half cycle (here, the entire circumference half cycle) when the half cycle PC10a corresponding to the time division frequency F10 is the entire cycle. .. Here, the full-circle half-cycle is a half-cycle PC10a divided into two, and the interval of the full-circle half-cycle is one half of the interval PC10a. That is, it can be said that the entire half cycle is a half cycle corresponding to twice the frequency of the time division frequency F10 of the time division clock CS10. Therefore, the number of divisions can be increased when the division is performed at the intervals of the entire circumference and half cycle, compared with the case where the division is performed at the interval PC10a.

In the present embodiment, the individual clocks that have been time-divided by the time division unit 75 are referred to as divided clocks DC ₁ , DC ₂ ,... DC _m . That is, the time division portion 75, a reference clock CS1 plurality of divided clock _{DC 1,} DC 2, so as to divide the · · · DC _m, performs time division intervals PC 10a. In FIG. 10, for convenience of explanation, the half cycle (interval) PC 10a is expressed longer than it actually is. However, actually, the half cycle PC 10a is set to be short, and the number of divisions of the reference clock CS1 is larger than the number of divisions of FIG.

Next, in step S109 of FIG. 8, the transmission clock creation unit 77 creates the transmission clock CS2 (see FIG. 7) to be transmitted to the ink head 40. Specifically, the transmission clock creating unit 77 selects and selects one divided clock for each divided clock DC ₁ , DC ₂ ,..., DC _m divided by the time division unit 75 in step S107. Any of the following processing A, processing B, and processing C is randomly performed on the divided clock.
Process A: Delete the selected divided clock.
Process B: A new divided clock is inserted immediately after the selected divided clock.
Process C: Neither process A nor process B is performed.

Here, in the process A, for example, in FIG. 10, the transmission clock creation unit 77 selects the divided clock DC _m . Then, the transmission clock creation portion 77 determines divided clock DC m _selected, and the portion of the reference print image data PD1 corresponding to the divided clock DC _m selected, whether or not there is a portion where the value is changed. When there is no portion where the value switches, the transmission clock creation unit 77 deletes the selected divided clock DC _m as shown in FIG. 7. As a result, the pulse period of the pulse P _n to which the deleted divided clock DC _m belongs changes from the period D _1n (see FIG. 10) to the period D _2n .

Incidentally, for example, when the transmission clock creation portion 77 selects the divided clock DC _4, the divided clock DC _4, there are parts which the value is changed at time _{T 12.} In this case, transmission clock creation portion 77 determines that it is not possible to remove the split clock DC _4, it does not perform the processing A on the divided clock DC _4. Similarly, for example, in the divided clock DC ₃ , the portion of the reference print image data PD1 corresponding to the divided clock DC ₃ has a portion whose value switches at time T ₂₁ . Therefore, if the divided clock selected is divided clocks DC _3, the transmission clock creation portion 77 determines that it is not possible to remove the split clock DC _3, no processing is performed A on the divided clock DC _3. In the present embodiment, the divided clock selected in the process A corresponds to the “first selected divided clock” of the present invention.

In the process B, for example, in FIG. 10, the transmission clock creating unit 77 selects the divided clock DC ₁ . Then, the transmission clock creation unit 77 inserts a new divided clock DC _{1 ′} immediately after the selected divided clock DC ₁ as shown in FIG. 7. As a result, the pulse cycle of the pulse P ₁ to which the selected divided clock DC ₁ belongs changes from the cycle D ₁₁ (see FIG. 10) to the cycle D ₂₁ . Here, the new divided clock DC _{1 ′} is such that the value at the rear end of the selected divided clock DC ₁ continues for the interval PC10a (in other words, the half cycle PC10a of the pulse PL10 of the time division clock CS10). It is a clock. The insertion interval PC10b, which is the interval of the new divided clock DC1 _' , has the same numerical value as the interval PC10a. In other words, in the process B, the transmission clock creation portion 77, while the value interval PC10a of the rear end of the selected divided clock DC _1, as further successive prolonging divided clock DC ₁ selected.

In FIG. 7, the transmission clock creation portion 77 selects the divided clock DC ₆ and divided clock DC _7, immediately after the divided clock DC ₆ and divided clock DC ₇ selected, a new division clock DC _{6 ',} and , A new divided clock DC _7'is inserted. In the present embodiment, the divided clock selected in the process B corresponds to the “second selected divided clock” of the present invention.

In the process C, for example, in FIG. 10, the transmission clock creating unit 77 selects the divided clock DC ₃ . Then, the transmission clock creation unit 77 does not perform any of the processing A and the processing B on the selected divided clock DC ₃ . That is, in the process C, the transmission clock creating unit 77 does not perform any process on the selected divided clock DC ₃ . In the present embodiment, the divided clock selected in the process C corresponds to the “third selected divided clock” of the present invention.

In the present embodiment, in step S109, the transmission clock creation unit 77 randomly performs any one of the above-described processing A, processing B, and processing C on the divided clock after the time division is performed in step S107. Done in. Therefore, any one of the process A, the process B, and the process C may be continuously performed on the continuous divided clocks. For example, in FIG. 10, the process B is performed on the continuous divided clocks DC ₆ and DC ₇ .

In step S109 of FIG. 8, after the transmission clock creating unit 77 creates the transmission clock CS2 as shown in FIG. 7, in step S111, the transmission print image data creating unit 78 creates the transmission clock CS2 created in step S109. pulse _{P 1, P 2, ···,} so as to correspond to the _{P n,} to create a transmission print image data PD2 of FIG. 7 from the reference print image data PD1 of FIG. Here, the transmission print image data creation unit 78 shortens the data rate (hereinafter, also referred to as rate) in the portion of the reference print image data PD1 corresponding to the divided clocks DC ₅ and DC _m for which the process A has been performed, for example. To do. The transmission print image data creation unit 78 lengthens the rate in the portion of the reference print image data PD1 corresponding to the divided clocks DC ₁ , DC ₆ , and DC ₇ for which the process B has been performed, for example. Further, the transmission print image data creation unit 78 does not perform any process in the portion of the reference print image data PD1 corresponding to the divided clock for which the process C has been performed, for example. In this way, as shown in FIG. 7, the transmission printing is performed by adjusting the rate of the reference print image data PD1 so as to correspond to the pulses P ₁ , P ₂ ,..., P _n of the transmission clock CS2. The image data PD2 is created.

Next, in step S113, the transmission unit 79 causes the transmission clock CS2 (see FIG. 7) created by the transmission clock creation unit 77 in step S109, and the transmission created by the transmission print image data creation unit 78 in step S111. The print image data PD2 (see FIG. 7) is transmitted to the control device 55 (see FIG. 4). Then, after the control device 55 receives the transmission clock CS2 and the transmission print image data PD2, the transmission unit 56 of the control device 55 transmits the transmission clock CS2 and the transmission print image data PD2 to the ink head 40. As a result, the ink head 40 ejects ink onto the recording medium 5 supported by the platen 25 based on the transmitted transmission clock CS2 and transmitted print image data PD2. When the transmission data creation device 60 is incorporated in the control device 55, the transmission of the transmission clock CS2 and the transmission print image data PD2 from the transmission unit 79 to the control device 55 may be omitted. In this case, for example, the transmission unit 79 directly transmits the transmission clock CS2 and the transmission print image data PD2 to the ink head 40 without passing through the control device 55.

As described above, the transmission clock CS2 and the transmission print image data PD2 shown in FIG. 7 are created for each of the plurality of ink heads 40. That is, each process of steps S107 to S113 of FIG. 8 is performed on each ink head 40. In transmission clock CS2 of the ink heads 40, each pulse _{P 1,} P 2, · · ·, pulse period _D 21 of _{P n, D 22, ···,} D 2n may be different.

As described above, in the present embodiment, as shown in FIG. 9, the time division frequency F10 of the time division clock CS10 is higher than the internal frequency F20 of the internal clock CS20. As shown in FIG. 10, when the reference clock CS1 is divided by the time division unit 75, the reference clock CS1 is divided at a half-cycle interval PC10a corresponding to a predetermined time division frequency F10 of the time division clock CS10. Since the interval PC10a becomes shorter as the frequency becomes higher, the number of divisions of the reference clock CS1 (in other words, the number of divided clocks) can be made larger as the interval PC10a becomes shorter. Further, in this embodiment, for example, by deleting the divided clock DC _m selected from a plurality of divided clocks, as shown in FIG. 7, the period D _{2n of the} pulse P _n to which the deleted divided clock DC _m belongs Is shortened. Therefore, the period D _2n of the pulse P _n can be different from the periods of other pulses. In the present embodiment, for example, when dividing the reference clock CS1, the number of divided clocks is larger than that when the internal clock CS20 is used. Therefore, there are many choices of the divided clocks that can be deleted, and the periods of the pulses P ₁ , P ₂ ,..., P _n can be set to various numerical values, so that the pulses P ₁ , P ₂ ,. .., It is easy to make the cycle of _Pn different. Therefore, it is easy to create the transmission clock CS2 having no specific frequency, and it is possible to suppress an increase in the level of radiation noise at the specific frequency. Therefore, in the present embodiment, it is possible to create the transmission clock CS2 that can suppress an increase in the level of generated radiation noise.

In the present embodiment, the time division clock creation unit 73 creates the time division clock CS10 based on the internal clock CS20 using the phase synchronization circuit 65 (see FIG. 6). Thus, by using the phase synchronization circuit 65, it is easy to create the time division clock CS10 from the internal clock CS20.

In the present embodiment, the time division frequency F10 of the time division clock CS10 is a numerical value between 1.5 times and 5 times the internal frequency F20 of the internal clock CS20. This makes it possible to reliably increase the number of divided clocks as compared with the case of using the internal clock CS20. Therefore, it is easy to create the transmission clock CS2 having no specific frequency, and it is possible to suppress an increase in the level of radiation noise at the specific frequency.

In the present embodiment, the transmission clock creation portion 77, for example, a plurality of divided clock _{DC 1,} DC 2, · · ·, after divided clock DC ₁ selected from DC _m, as shown in FIG. 7, divided clock A new divided clock DC _{1 ′} that is continuous is inserted while the value of the rear end of DC ₁ is the interval PC10a corresponding to the half cycle of the time division clock CS10. As described above, in the present embodiment, by inserting the new divided clock DC _{1 ′} after the selected divided clock DC ₁ , that is, between the divided clock DC ₁ and the divided clock DC ₂ , the divided clock DC ₁ is inserted. The pulse period D ₂₁ of the pulse P ₁ to which ₁ belongs can be lengthened. Therefore, the pulse period D ₂₁ of the pulse P ₁ can be made different from the pulse periods of the other pulses, so that the transmission clock CS2 having no specific frequency can be created.

In this embodiment, the new division is an interval of the clock DC _{1 'insertion} interval PC 10b (see FIG. 7), when the interval of the half period PC10a corresponding to the divided frequency F10 when the divided clock CS10, i.e., time division unit It is the same numerical value as the interval PC10a of the divided clock divided by 75. In this way, by making the insertion interval PC10b and the interval PC10a the same, it is possible to prevent the processing from becoming complicated and to shorten the processing time.

In the present embodiment, the transmission clock creating unit 77 does not perform any processing on the divided clock DC ₃ selected from the plurality of divided clocks DC ₁ , DC ₂ ,..., DC _{m in} FIG. 10, for example. .. Temporarily, for all the divided clocks DC ₁ , DC ₂ ,..., DC _m , the process A is a process of deleting the selected divided clock, and the process B is a new divided clock. If any of the inserting processes is performed, the processing time becomes long. However, for example, the processing time can be shortened by the processing C in which no processing is performed on the selected divided clock DC ₃ . Further, since any one of the three types of processing A to C is performed on each divided clock DC ₁ , DC ₂ ,..., DC _m , any one of the processing A and the processing B is performed. The pulse periods D ₂₁ , D ₂₂ ,..., D _2n are likely to be different from each other as compared with the case where the bending is performed. Therefore, it is easy to create the transmission clock CS2 in which the radiation noise is more dispersed.

In this embodiment, the printer 100 is a so-called large-sized printer. Here, the length of the platen 25 in the main scanning direction Y is 20 inches or more. The larger the printer, the higher the current that flows toward the ink head 40, so that radiation noise is more likely to occur. However, in the present embodiment, the transmission data creation device 60 creates the transmission clock CS2 having no specific frequency for each ink head 40. Therefore, even with a large printer, it is possible to suppress an increase in the level of generated radiation noise. Therefore, creating such a transmission clock CS2 is particularly useful for large printers.

The preferred embodiment of the present invention has been described above. However, the above embodiments are merely examples, and the present invention can be implemented in various other modes. Next, another embodiment will be briefly described. In the following description, the same components as those already described will be denoted by the same reference numerals, and the description thereof will be appropriately omitted.

<Second Embodiment>
Next, a printer according to the second embodiment will be described. In the first embodiment, the transmission clock CS2 respectively transmitted to the four ink heads 40 and the time division clock CS10 used when creating the transmission print image data PD2 are clocks having a common frequency. Therefore, the reference clock CS1 for each ink head 40 is divided based on the time division clock CS10 having the same frequency. However, in the second embodiment, at least part of the time division clock used when dividing the reference clock CS1 when creating the transmission clock CS2 and the transmission print image data PD2 transmitted to each ink head 40. The frequency of the time division clock may be different from the frequency of other time division clocks.

In the following description, as shown in FIG. 3, the four ink heads 40 will be referred to as a first ink head 41, a second ink head 42, a third ink head 43, and a fourth ink head 44, respectively. FIG. 11 is a time chart showing the internal clock CS20 and the first to fourth time division clocks CS11 to CS14 according to the second embodiment. In the present embodiment, the time division clock generation unit 73, as shown in FIG. 11, based on the internal clock CS20, the first time division clock CS11, the second time division clock CS12, and the third time division clock. The four clocks CS13 and the fourth time division clock CS14 are created. For example, the second time division clock CS12 is an example of the "other time division clock" of the present invention. Here, the time-division clocks CS11, CS12, CS13, and CS14 are time-division of the transmission clock CS2 transmitted to the ink heads 41, 42, 43, and 44, and the reference clock CS1 used to create the transmission print image data PD2. It is a clock used at the time of.

Here, the frequencies of the time division clocks CS11, CS12, CS13, and CS14 are referred to as a first frequency F11, a second frequency F12, a third frequency F13, and a fourth frequency F14, respectively. The first to fourth frequencies F11 to F14 are higher than the internal frequency F20 which is the frequency of the internal clock CS20. In other words, the pulse periods PC11 to PC14 corresponding to the first to fourth frequencies F11 to F14 are shorter than the pulse period PC20 corresponding to the internal frequency F20. In the present embodiment, at least one frequency among the first to fourth frequencies F11 to F14 is a numerical value different from other frequencies. For example, like the present embodiment, the first to fourth frequencies F11 to F14 may have different numerical values. For example, the first frequency F11 and the second frequency F12 may be the same numerical value, and the third frequency F13 and the fourth frequency F14 may be different numerical values and different from the first frequency F11.

For example, when the numerical values of the first frequency F11 and the second frequency F12 are different, the first frequency F11 and the second frequency F12 are the common divisors of the first frequency F11 and the second frequency F12, and the first frequency F11 and the second frequency F12. It is preferable that the numerical value of both the frequencies F12 is not included. For example, when the first frequency F11 is 50 MHz and the second frequency F12 is 200 MHz (hereinafter, referred to as “first case”), the common divisor of the first frequency F11 and the second frequency F12 (here, The greatest common divisor) includes 50. In the first case, all the data rates that can be generated at the first frequency F11 are the data rates that can be generated at the second frequency F12. As described above, the data rate generated at the first frequency F11 is generated at the second frequency F12, which is referred to as "data rate overlay". In the first case, the data rate is overlaid on the second frequency F12 with respect to all the data rates generated on the first frequency F11.

On the other hand, for example, when the first frequency F11 is 120 MHz and the second frequency F12 is 200 MHz (hereinafter, the second case), the common divisors of the first frequency F11 and the second frequency F12 are 120 and 200. Both numbers are not included. In the second case, the data rate that can be generated at the first frequency F11 includes a data rate that is not included in the data rate that is generated at the second frequency F12. Therefore, for example, when the second frequency F12 is 200 MHz, the first frequency F11 is preferably 120 MHz rather than 50 MHz. When the numerical values of the first frequency F11 and the second frequency F12 are different, the first frequency F11 and the second frequency F12 are not included in the common divisors of the first frequency F11 and the second frequency F12, and the first frequency F11 is included. In addition, by setting the value so that the second frequency F12 is not included, the time division timing at the time of creating the transmission data for the first ink head 41 and the time division at the time of creating the transmission data for the second ink head 42 It is easy to change the timing.

Further, in the present embodiment, for example, a value obtained by dividing the first frequency F11 by the greatest common divisor of the first frequency F11 and the second frequency F12 (hereinafter, simply referred to as the “greatest common divisor”), and The value obtained by dividing the two frequencies F12 by the greatest common divisor is preferably relatively large. The value x divided by the greatest common divisor means that when the data rates that can be generated at the frequency are arranged in the descending order (or the ascending order), the data rate is overlaid every (x-1). For example, when the value obtained by dividing by the greatest common divisor is “3”, when the data rates that can be generated at that frequency are arranged in descending order, the data rate is overlaid every two. Therefore, the larger the value divided by the greatest common divisor, the less the data rate is covered between the two frequencies.

For example, when the first frequency F11 is 50 MHz and the second frequency F12 is 200 MHz as in the first case, the greatest common divisor is 50, and the first common frequency F11 and the second frequency F12 are the greatest common divisor ( Here, the values when divided by 50) are 1 and 4, respectively. When the first frequency F11 is 120 MHz and the second frequency F12 is 200 MHz as in the second case, the greatest common divisor is 40, and the first common frequency F11 and the second frequency F12 are the greatest common divisor (here, The values when divided by 40) are 3 and 5, respectively. For example, when the first frequency F11 is 110 MHz and the second frequency F12 is 200 MHz (hereinafter, referred to as the third case), the greatest common divisor is 10, and the first frequency F11 and the second frequency F12 are the greatest common divisor. The values when divided by (here, 10) are 11 and 20, respectively. Of the first to third cases, the frequency combination in the third case, which has the largest value when divided by the greatest common divisor, is the combination in which the occurrence of the data rate is reduced. In the present embodiment, the value when the first frequency F11 is divided by the greatest common divisor and the value when the second frequency F12 is divided by the greatest common divisor are preferably, for example, 3 or more, respectively. In the first to third cases, the frequency combination in the second case is more preferable than the frequency combination in the first case, and the frequency combination in the third case is more preferable.

In addition, although the relationship regarding the common divisor at the first frequency F11 and the second frequency F12 has been described above, the common divisor at the other two frequencies of the first to fourth frequencies F11 to F14 is the same as the above. The same can be said.

In the present embodiment, the storage unit 70 stores the frequency of the reference clock CS1 for each of the ink heads 41 to 44. These reference clocks CS1 may be the same for all of the ink heads 41 to 44, or at least some of them may be different.

The time division unit 75 divides the reference clock CS1 for the first ink head 41 and the reference print image data PD1 at half-cycle PC11a intervals corresponding to the first frequency F11 of the first time division clock CS11. Similarly, the time division unit 75 divides the reference clock CS1 for the second ink head 42 and the reference print image data PD1 at intervals of a half cycle PC12a corresponding to the second frequency F12 of the second time division clock CS12. , The reference clock CS1 for the third ink head 43 and the reference print image data PD1 are divided at intervals of a half cycle PC13a corresponding to the third frequency F13 of the third time division clock CS13. Further, the time division unit 75 divides the reference clock CS1 for the fourth ink head 44 and the reference print image data PD1 at intervals of the half cycle PC 14a corresponding to the fourth frequency F14 of the fourth time division clock CS14.

In this embodiment, the control of the transmission clock creation unit 77 and the transmission print image data creation unit 78 is substantially the same as that of the first embodiment. The transmission clock creation unit 77 is one of the above-described processes A to C with respect to each reference clock CS1 divided by the time division unit 75 and the division clock of the reference clock CS1 for each ink head 41 to 44. Process is performed randomly. As a result, the transmission clock creation unit 77 creates the transmission clock CS2 for each of the ink heads 41 to 44. In this embodiment, the transmission clock creation unit 77 creates four transmission clocks CS2.

The transmission print image data creation unit 78 adjusts the data rate of the reference print image data PD1 of each ink head 41 to 44 so as to correspond to the transmission clock CS2 for each ink head 41 to 44. The transmission print image data PD2 for 41 to 44 is created.

As described above, in the present embodiment, when the transmission data for each of the ink heads 41 to 44 is created, the first to fourth of the first to fourth time division clocks CS11 to CS14 that serve as a reference when the reference clock CS1 is time-divided. At least one of the fourth frequencies F11 to F14 has a different numerical value from the other frequencies. This makes it easy to change the division timing with respect to the reference clock CS1 for the ink heads 41 to 44. Therefore, in the transmission clock CS2 of each of the ink heads 41 to 44, it is easy to change the pulse cycle. Therefore, when transmitting the transmission data between the ink heads 41 to 44, it is possible to make it difficult to generate radiation noise at the same timing, and thus it is possible to suppress an increase in the level of radiation noise.

In the present embodiment, the first to fourth frequencies F11 to F14 are higher than the internal frequency F20. As a result, when the reference clock CS1 is divided, the division interval can be shortened, and the number of divisions of the reference clock CS1 (in other words, the number of divided clocks) can be increased. Since the number of divided clocks is large, the timing of performing any of the processes A to C is large, and the pulse cycle can be set to various numerical values. Therefore, it is easy to change the pulse interval. Therefore, it is easy to create the transmission clock CS2 having no specific frequency, and it is possible to suppress an increase in the level of radiation noise at the specific frequency.

When the first frequency F11 and the second frequency F12 are different and the common divisor of the first frequency F11 and the second frequency F12 includes the first frequency F11, the first frequency F11 of the first time division clock CS11. The division timing when the division is performed at the interval of the half cycle PC 11a corresponding to is at least the division timing when the division is performed at the interval of the half cycle PC 12a corresponding to the second frequency F12 of the second time division clock CS12. Will be the same. Therefore, in this case, the timing at which the radiation noise occurs is likely to be the same. However, in the present embodiment, for example, the first frequency F11 and the second frequency F12 do not include the first frequency F11 and the second frequency F12 in the common divisor of the first frequency F11 and the second frequency F12. It is a number that cannot be seen. Therefore, in this case, it corresponds to the division timing when dividing at the interval of the half cycle PC11a corresponding to the first frequency F11 of the first time division clock CS11 and the second frequency F12 of the second time division clock CS12. It is easy to make the division timing different when the division is performed at the interval of the half cycle PC 12a. Therefore, it is difficult for the radiation noise to occur at the same timing.

In the present embodiment, the value obtained by dividing the first frequency F11 by the greatest common divisor of the first frequency F11 and the second frequency F12, and the second frequency F12 are the first frequency F11 and the second frequency F12. The value when divided by the greatest common divisor of is 3 or more, respectively. In this way, by increasing the value when divided by the greatest common divisor, the above-mentioned data rate loss is reduced between two frequencies (for example, the first frequency F11 and the second frequency F12). be able to. Since it is possible to make radiation noise less likely to occur at the same timing by reducing the data rate loss, it is possible to suppress an increase in the radiation noise level.

In each of the above-described embodiments, the printer 100 is a so-called roll-to-roll type printer. Therefore, in each of the above-described embodiments, the recording medium 5 on the platen 25 is configured to move in the sub-scanning direction X with respect to the platen 25. However, the present invention can be applied to so-called flatbed printers. In this case, the recording medium is supported by a flat bed (in other words, a table). In this case, as the flat bed moves in the sub-scanning direction X, the recording medium 5 supported by the flat bed moves in the sub-scanning direction X.

40 Ink head 60 Transmission data creation device 65 Phase synchronization circuit (PLL)
70 storage unit 73 time division clock creation unit 75 time division unit 77 transmission clock creation unit 78 transmission print image data creation unit (print image data creation unit)
100 Printer (inkjet printer)
CS1 Reference clock CS2 Transmission clock CS10 Time division clock CS20 Internal clock

Claims (12)

In a printer having an ink head for ejecting ink, transmission data having transmission print image data which is print image data transmitted to the ink head and transmission clock which is a clock transmitted to the ink head is created. A transmission data creation device,
A reference clock that is a clock having a plurality of pulses with the same period, and a storage unit that stores reference print image data that is print image data corresponding to the reference clock,
An internal clock whose frequency is a predetermined internal frequency,
A time division clock generation unit that generates a time division clock whose frequency is a predetermined first frequency higher than the internal frequency of the internal clock based on the internal clock;
Based on the half cycle corresponding to the first frequency of the time division clock, at the half cycle, or at intervals of the full circumference half cycle which is a half cycle of the full cycle when the half cycle is a full cycle. A time division unit that divides the reference clock into a plurality of divided clocks by dividing the reference clock;
A transmission clock generation unit that uses the reference clock after deleting the first selected divided clock as the transmission clock when one divided clock selected from the plurality of divided clocks is a first selected divided clock;
A print image data creating unit that creates the transfer print image data by adjusting the data rate of the reference print image data so as to correspond to the transfer clock created by the transfer clock creating unit;
A transmission data creation device equipped with. Equipped with a phase synchronization circuit,
The transmission data creation device according to claim 1, wherein the time-division clock creation unit creates the time-division clock based on the internal clock using the phase synchronization circuit. The transmission data creation device according to claim 1 or 2, wherein the first frequency is a numerical value between 1.5 times and 5 times the internal frequency. When the other selected divided clock selected from the plurality of divided clocks divided by the time division unit is set as the second selected divided clock, the transmission clock creation unit is configured to perform the operation after the second selected divided clock. 4. The transmission clock according to claim 1, wherein the transmission clock is the reference clock after inserting new continuous divided clocks while the value of the rear end of the second selected divided clock is a predetermined insertion interval. The described transmission data creation device. The transmission data creation device according to claim 4, wherein the insertion interval has the same numerical value as the interval of the half cycle corresponding to the first frequency or the full circumference half cycle. The transmission clock creating unit determines, with respect to the third selected divided clock, another one of the divided clocks divided by the time division unit as a third selected divided clock. The transmission data creation device according to any one of claims 1 to 5, which does not perform the process. The storage unit stores another reference clock that is a clock having a plurality of pulses with the same period, and other reference print image data that is print image data corresponding to the other reference clock,
The time division clock generation unit further generates another time division clock whose frequency is a second frequency different from the first frequency, based on the internal clock,
The time division unit may further include, based on a second half cycle, which is a half cycle corresponding to the second frequency, a second half cycle, or a half cycle when the second half cycle is a full cycle. Dividing the other reference clock into a plurality of other divided clocks by dividing the other reference clock at an interval of a certain second full-half cycle.
The transmission clock creating unit further deletes the other first selected divided clock when the other selected divided clock selected from the plurality of other divided clocks is the other first selected divided clock. The other reference clock of is another transmission clock transmitted to another ink head different from the ink head,
The print image data creation unit adjusts the data rate of the other reference print image data so as to correspond to the other transmission clock created by the transmission clock creation unit, so that the other ink head The transmission data creation device according to claim 1, which creates other transmission print image data to be transmitted. The transmission data creation device according to claim 7, wherein the second frequency is higher than the internal frequency. The first frequency and the second frequency are values such that the common divisor of the first frequency and the second frequency does not include the first frequency and does not include the second frequency. The transmission data creation device according to claim 7 or 8. The value when the first frequency is divided by the greatest common divisor of the first frequency and the second frequency, and the value when the second frequency is divided by the greatest common divisor are 3 or more, respectively. The transmission data creation device according to any one of claims 7 to 9, wherein A transmission data creation device according to any one of claims 1 to 6,
An ink head that ejects ink,
The transmission clock created by the transmission clock creation unit, and a transmission unit that sends the transmission print image data created by the print image data creation unit to the ink head;
An inkjet printer equipped with. A transmission data creation device according to any one of claims 7 to 10,
An ink head that ejects ink,
Another ink head different from the ink head,
The transmission clock created by the transmission clock creation unit and the transmission print image data created by the print image data creation unit are transmitted to the ink head, and the transmission clock creation unit creates the transmission clock image data. Another transmission clock, and a transmission unit that transmits the other transmission print image data created by the print image data creation unit to the other ink head,
An inkjet printer equipped with.

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