JP3870461B2 - Printer and printer drive device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a printer capable of multi-gradation recording, and relates to a printer driving apparatus and printer capable of multi-gradation recording that can be used as a hard copy device for recording gradation image data from a computer or the like.
[0002]
[Prior art]
Conventionally, in a printer that performs recording using binary gradation data, ON / OFF recording is performed according to binary data by a plurality of recording elements provided in a recording head. For example, in an ink jet printer, image data for each ejection of each nozzle by a print head having a plurality of ejection nozzles is transferred to the head drive IC, and ink is ejected from the transferred image data to form an image. Had gone.
[0003]
In recent years, gradation recording has been performed by various printers, and ink jet printers have also been performed in the same manner as other printers. As one of gradation recording, there is a method of changing the number of dots ejected to one pixel. This method has the same effect as changing the size of dots during ejection. In the case of this gradation recording, conventional binary gradation data in which data for one pixel is composed of a plurality of bits and one ink ejection, that is, a signal for each bit is serially transferred to the head by a plurality of nozzles. Ink jetting was performed in the same manner as the recording by, and image formation was performed.
[0004]
For example, Japanese Patent Publication No. 4-31220 uses a thermal transfer printer to convert gradation data of a plurality of bits into 1 bit, that is, after converting it into data corresponding to one recording, and then serially transferring the data to registers and latches. It is described. Japanese Patent Publication No. 4-74906 describes a device that converts gradation data of a plurality of bits into serial data and generates pulses having different numbers of pulses from serially transferred data for one pixel.
[0005]
[Problems to be solved by the invention]
However, since Japanese Patent Publication No. 4-31220 and Japanese Patent Publication No. 4-74906 transfer image data serially to the head, that is, in units of 1 bit, it takes a longer time to record than when recording binary image data. . For example, when gradation recording is performed with 16 gradations, it takes 16 times longer to transfer a signal to the head than when gradation recording is not performed. The recording of the gradation data is executed by repeating a recording operation similar to the binary recording for one pixel a plurality of times. In the case of transferring gradation data to the head serially, for example, only one drive signal of a plurality of recording operations can be transferred to the head per clock.
[0006]
Accordingly, when image data is transferred serially to the head in gradation recording, at least one number of gradations are required to complete recording of one pixel, and thus recording of one pixel is completed in one clock. For recording by value, there arises a serious problem of signal transfer and the accompanying decrease in recording speed.
[0007]
Therefore, in a configuration in which image data is serially transferred to the head with a multi-tone printer, a configuration in which the recording operation of the head is increased by increasing the transfer frequency can be considered in order to solve the decrease in recording speed.
[0008]
However, another problem arises particularly in an ink jet printer or the like in which a head is mounted on a carriage and recording is performed by scanning in the main scanning direction. In an inkjet printer or the like, the carriage moves with a head and a head driver mounted thereon. The carriage movement width depends on the size of the recording material, and for an inkjet printer that records on A4 size recording paper, it is 20 cm or more, so a long flexible cable such as a parallel cable is used between the carriage and the control board. It is connected. Connecting a carriage and a control board with a long flexible cable such as an ink jet printer to transfer high-frequency data as gradation data may cause noise in the cable, which may cause radio interference, etc. It is not appropriate from the point of view.
[0009]
In addition, if it is intended to provide a multi-tone printer capable of outputting a higher quality image, the number of gradations increases, the number of data increases, the head drive frequency becomes more and more difficult to control.
[0010]
The present invention solves such a problem, and by performing gradation recording using image data composed of parallel data having a plurality of bits having gradation information, it is possible to increase the speed without increasing the driving frequency of the head driver. It is an object of the present invention to provide a multi-tone printer driving apparatus and multi-tone printer that perform gradation recording.
[0011]
In addition, parallel data having gradation in the head portion is converted into the number of droplet ejections to obtain gradation recording.
[0012]
[Means for Solving the Problems]
The above-mentioned purpose is that after each pixel is composed of a plurality of bits indicating gradation, and the data of the plurality of bits is inputted in parallel, and the pixel data is sequentially stored for each pixel, and a predetermined number of pixel data is stored. A first storage means for outputting the stored pixel data in parallel; a count means for generating a counter signal; and an output of the first storage means, and the first storage means A plurality of comparison means for comparing each pixel data with the counter signal and outputting a drive signal in accordance with the comparison result, and a drive signal from each comparison means provided corresponding to each comparison means. According to the present invention, there is provided recording means that is driven based on the driving voltage that is changed in response, and selection means for selecting an output of the comparison means and causing recording to be performed by a desired recording means among the recording means. Pudding It is achieved by the driving device.
[0013]
In addition, the above-mentioned purpose is composed of a plurality of bits indicating gradations per pixel, and the data of the plurality of bits is inputted in parallel to sequentially store the pixel data for each pixel and store a predetermined number of pixel data. After that, the first storage means for outputting the stored pixel data in parallel, the second storage means for latching and outputting the pixel data output in parallel by the first recording means, and the counter signal The counter means is provided corresponding to each of the generated counting means and the output of the second storage means, and each pixel data of the second storage means is compared with the counter signal, and a drive signal is determined according to the comparison result. A plurality of comparison means for outputting, a recording means provided corresponding to each comparison means and driven based on a drive voltage changed according to a drive signal from each comparison means, and the comparison means Select the output It is achieved by the drive unit of the printer, characterized in that it has a selection means for causing recording by a desired recording means among the recording means.
[0014]
In addition, the above object is composed of a plurality of bits indicating gradation per pixel, and the data of the plurality of pixels is sequentially input in parallel from the lower bits or the upper bits of the plurality of bits to sequentially store the pixel data, After storing a predetermined number of pixel data, a first storage means for outputting the stored pixel data in parallel, and a second storage means for outputting the parallel output by latching the pixel data output in parallel by the first recording means A storage means, a counting means for generating a counter signal, provided corresponding to each output of the second storage means, and comparing each pixel data of the second storage means with the counter signal; A plurality of comparison means for outputting a drive signal according to the comparison result, and a recording provided corresponding to each comparison means and driven based on the drive voltage changed according to the drive signal from each comparison means means , Selects the output of the comparing means, is achieved by a driving device of a printer, characterized in that it has a selection means for causing recording by a desired recording means among the recording means.
[0015]
In addition, the above-mentioned purpose is composed of a plurality of bits indicating gradations per pixel, and the data of the plurality of bits is inputted in parallel to sequentially store the pixel data for each pixel and store a predetermined number of pixel data. After that, the first storage means for outputting the stored pixel data in parallel, the counting means for generating a counter signal, and the output of the first storage means are provided corresponding to each of the first storage means A plurality of comparison means for comparing each pixel data of the storage means with the counter signal and outputting a drive signal according to the comparison result, and driving provided from each comparison means and corresponding to each comparison means A recording unit driven based on a driving voltage changed according to the signal; a selection unit for selecting an output of the comparison unit and causing a desired recording unit to perform recording among the recording units; and the first unit Memory of A data transfer unit between the carriage, which includes the comparison unit, the recording unit, and the selection unit and is movably held during recording, and the carriage and the substrate included in the printer body, and has flexibility. And a printer having data transfer means for following the movement of the carriage.
[0016]
In addition, the above-mentioned purpose is composed of a plurality of bits indicating gradations per pixel, and the data of the plurality of bits is inputted in parallel to sequentially store the pixel data for each pixel and store a predetermined number of pixel data. The first storage means for outputting the stored pixel data in parallel, the second storage means for latching and outputting the pixel data output in parallel by the first storage means, and the counter signal The counter means is provided corresponding to each of the generated counting means and the output of the second storage means, and each pixel data of the second storage means is compared with the counter signal, and a drive signal is determined according to the comparison result. A plurality of comparison means for outputting, a recording means provided corresponding to each comparison means and driven based on a drive voltage changed according to a drive signal from each comparison means, and an output of the comparison means Select Among the means, there is provided a selection means for recording by a desired recording means, the first storage means, the second storage means, the comparison means, the recording means, and the selection means, and can be moved during recording. And a printer having data transfer means for transferring data between the carriage and a substrate provided in the printer main body and having flexibility and following movement of the carriage Is achieved.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to FIGS. 1 to 8, taking an inkjet printer as an example.
[0019]
FIG. 1 is a perspective view showing a main part of the ink jet printer 1.
[0020]
The carriage 2 is a resin case that houses the head 3 and the head driver 16. The head driver 16 housed in the carriage 2 is composed of an IC, and is connected to the control board 9 by a flexible cable 5 drawn from the carriage 2.
[0021]
The carriage 2 is reciprocated in the main scanning direction indicated by an arrow X in the figure by the carriage driving mechanism 6. The carriage drive mechanism 6 includes a motor 6a, a pulley 6b, a toothed belt 6c, and a guide rail 6d, and the carriage 2 is fixed to the toothed belt 6c.
[0022]
When the pulley 6b is rotated by the motor 6a, the carriage 2 fixed to the toothed belt 6c is moved along the direction of the arrow X in the drawing. The guide rail 6d is two round bars parallel to each other and passes through the insertion hole of the carriage 2 so that the carriage 2 slides. For this reason, the toothed belt 6c is not bent by the weight of the carriage 2, and the reciprocating direction of the carriage 2 is in a straight line. The direction in which the carriage 2 moves can be changed by reversing the rotation direction of the motor 6a, and the moving speed of the carriage 2 can be changed by changing the number of rotations.
[0023]
The ink cartridge 4 has an ink tank inside. The ink supply port of the ink tank opens when the ink cartridge 4 is set on the carriage 2 and is connected to the ink supply pipe, and is closed when the connection is released, and ink is supplied to the head 3. The carriage 2 is provided with a mounting portion for the ink cartridge 4 so that an ink cartridge containing Y, M, C, and K inks for ejection can be attached and detached. In this embodiment, only K (black) ink tanks of the four colors are stored in another cartridge, and the other three color ink tanks are stored in one cartridge.
[0024]
The flexible cable 5 relates to the data transfer means of the present invention, and is a flexible film in which a wiring pattern including data signal lines, power supply lines, etc. is printed on a flexible film, and data is transferred between the carriage 2 and the control board 9. Transfer and follow the movement of the carriage 2.
[0025]
The encoder 7 is a resin transparent film with a scale at predetermined intervals, and the scale is detected by an optical sensor provided on the carriage 2 to detect the moving speed of the carriage 2.
[0026]
The paper transport mechanism 8 is a mechanism for transporting the recording paper P in the sub-scanning direction indicated by an arrow Y in the figure, and includes a transport motor 8a and transport roller pairs 8b and 8c. The transport roller pair 8b and the transport roller pair 8c are driven by a transport motor 8a and are roller pairs that are substantially equal to each other by a gear train (not shown), but the transport roller pair 8c rotates at a slightly faster peripheral speed. The recording paper P is sandwiched between a pair of transport rollers 8b that have been fed from a paper feed mechanism (not shown) and rotated at a constant speed, and the direction of transport in the sub-scanning direction is controlled by a paper feed guide (not shown). After being corrected, the sheet is sandwiched and transported by the transport roller pair 8c. Since the peripheral speed of the conveyance roller pair 8c is slightly faster than that of the conveyance roller pair 8b, the recording paper P passes through the recording unit without causing slack. The speed at which the recording paper P moves in the sub-scanning direction is set to a constant speed.
[0027]
In this way, while moving the recording paper P at a constant speed in the sub-scanning direction, the carriage 2 is moved at a constant speed in the main scanning direction, and the ink ejected from the head 3 is adhered to a predetermined range on one side of the recording paper P. Record an image on
[0028]
FIG. 2 is a circuit block diagram of the ink jet printer 1.
[0029]
The control board 9 is mounted with a CPU 11 that controls the entire inkjet printer 1 and is connected to the head driver 16 of the carriage 2 by the flexible cable 5 as described above.
[0030]
The page memory 12 stores image data received from a personal computer or the like that uses the inkjet printer 1 itself as a peripheral device. The storage capacity of the page memory 12 may be determined by the number of bits of gradation image data handled by a personal computer or the like, the number of dots, the signal transfer speed, the CPU processing speed, and the like.
[0031]
Since the multi-tone printer driving apparatus according to the present invention enables very high-speed recording, the parallel interface SCSI (14a) and IEEE1284 (14b) are used for the purpose of speeding up image data transfer without using a serial interface. Was made available.
[0032]
The line memories 13a and 13b are related to the third storage means of the present invention, and are used as line memories for storing image data of each pixel recorded in a line in the main scanning direction when recording on the recording paper P. Each image data is transferred from the page memory 12 as gradation data of several bits. In this embodiment, two 8-bit processing line memories 13a and 13b are used in parallel. However, a single line memory for 16-bit processing may be used. The data signal line from the page memory 12 has 16 bits and branches to each line memory 13 by 8 bits. The image data in the line memories 13a and 13b is transferred to the head driver 16 via the flexible cable 5.
[0033]
The head drivers 16a to 16d are composed of ICs, and one head driver is provided for each color. Each IC is connected to a shift register according to the first storage means of 128 bits × 4 according to the present invention, and the image data from the line memories 13a and 13b is temporarily stored in this shift register. A plurality of head drivers 16 may be provided for each color, and the size can be further reduced by packaging drivers for four colors in one IC. The head driver 16 has a 4-bit data signal line, and when the head driver 16 is serially connected by this signal line, the image data that could not be stored in the preceding shift register is stored in the subsequent shift register. it can.
[0034]
The four color heads 17Y, 17M, 17C, and 17K according to the recording means of the present invention each have 128 nozzles, and the nozzles constituting each head are arranged in the sub-scanning direction so that a plurality of lines can be recorded simultaneously. Has been placed. The combination of the head driver 16 and the head 17 according to the present embodiment is an example of an embodiment of a driving device for a multi-tone printer according to the present invention.
[0035]
In the present embodiment, yellow image data is transferred from the line memory 13a to the head driver 16a through a 4-bit data signal line. The 128 pieces of yellow image data transferred to the head driver 16a are processed in parallel, and recording by the head 17Y is executed. Similarly, the magenta image data is transferred from the line memory 13a to the head driver 16b and recorded by the head 17M. Cyan is transferred from the line memory 13b to the head driver 16c and recording is performed by the head 17C, and black is transferred from the line memory 13b to the head driver 16e and recording is performed by the head 17K. Detailed operation of the head driver 16 will be described later.
[0036]
The AND gate 22 sends a TRGIN signal for starting ink ejection to the head driver 16 when the carriage 2 starts one reciprocating movement based on the information detected by the encoder 7 and reaches a predetermined position on the forward path. Output. The head driver 16 receives this TRGIN signal, sends a drive signal, and ejects ink by the head 17.
[0037]
The head driver 16 supplies a drive signal to the electromechanical conversion element provided in each nozzle of the head 17 through a 128-bit data signal line, and the electromechanical conversion element is deformed in response to the drive signal, thereby causing ink in the head. Is injected. There are various types of electromechanical conversion elements. In this embodiment, a piezoelectric element will be described as an example.
[0038]
In general, ink jet printers perform recording by ejecting liquid droplets from nozzles in accordance with drive signals. Sequential ink droplets are recorded on the recording paper P, and recording of an area corresponding to the number of droplets becomes possible, so that gradation recording can be performed.
[0039]
Further, the speed of the droplets ejected from the nozzle head 17 can be increased by increasing the drive voltage of the piezo element. Utilizing this, if the applied voltage of each ejection is gradually increased for each pulse, the sequentially ejected ink droplets can be recorded at a closer position on the recording paper P, and gradation recording with higher image quality is possible. Is possible.
[0040]
Furthermore, a stable image quality can be obtained by using different waveforms for the drive signal depending on the surrounding environment of the inkjet printer 1. In this embodiment, the thermistor 19 measures the temperature near the head 17 and changes the waveform according to the measured temperature. With this configuration, even when the ink viscosity changes with temperature, the head can be driven in response thereto. In addition, it is more preferable if the humidity condition or the like is a parameter for changing the waveform of the drive signal.
[0041]
Since the waveform of the drive signal needs to be changed every time when one ink droplet is ejected in this way and also depending on the environment, various waveforms of the drive signal are stored in the serial ROM 20 as digital data. The serial ROM 20 can be configured using an EPRROM or the like.
[0042]
The serial ROM 20 stores drive signal waveform data in which the applied voltage is gradually increased for each pulse for each temperature condition. In the present embodiment, data of 4 bits and 16 gradations per color is output. Therefore, the waveform data stored in the serial ROM 20 is obtained by converting the waveform of the basic waveform into 16 digital data by gradually increasing the amplitude.
[0043]
The CPU 11 reads waveform data optimum for the temperature condition detected by the thermistor 19 from the serial ROM 20 and sends it to the drive waveform generation circuit 15. The drive waveform generation circuit 15 demodulates and amplifies the waveform data of the drive signal into an analog waveform by D / A conversion, and outputs it to the head driver 16.
[0044]
Next, the block diagram of the head driver in FIG. 3 will be described. The head driver 16 of the present embodiment is an example of a shift register 31 that is an example of the first storage unit of the present invention, a latch 32 that is an example of the second storage unit of the present invention, and a comparison unit of the present invention. The digital comparator 33 includes a selection gate 34 which is an example of the selection means of the present invention, a level shifter 35, a driver 36, a counter 37, and the like. In this embodiment, in order to process image data consisting of 16 gradations per pixel, each means constituting the head driver 16 has a configuration corresponding to 4 bits.
[0045]
Gradation image data in which one pixel is a plurality of bits, here 4 bits, is transferred from the line memory 13 to the head driver 16 serially in units of pixels. FIG. 3 shows a state in which the first 4-bit pixel data DAT0, DAT1, DAT2, and DAT3 are transferred through a 4-bit data signal line.
[0046]
The shift register 31 has a capacity capable of storing image data of a number of pixels corresponding to one ejection by the nozzle head 17. In the present embodiment, image data for 128 pixels arranged in the sub-scanning direction is stored. When the carriage 2 reaches a position suitable for recording, the control circuit 23 outputs a LOAD signal, and the latch 32 latches the image data output in parallel from the shift register 31 when receiving the LOAD signal.
[0047]
In this way, by transferring the image data of the number of nozzles 128 × 4 bits in parallel in units of 4 bits, the data transfer, and hence the drive time of the recording head can be reduced to 1/16. This reduction effect becomes greater as the number of ink droplets ejected per pixel, which is the number of gradations, increases.
[0048]
The digital comparator 33 relates to the comparison means of the present invention, and compares the value of the image data latched by the latch 32 with the count value of the counter 37. In this example, since the image data is 4 bits per pixel, a 4-bit counter is used. A counter corresponding to the number of bits of the image data may be appropriately used as the counter as the comparison means. The digital comparator 33 outputs a Hi level when the value of the image data is greater than or equal to the count value, outputs a Low level when the value of the image data is less than the count value, and the output state is the previous level until the comparison result changes. Maintain state.
[0049]
The digital comparator 33 converts the parallel data of a plurality of bits into 1-bit continuous data that is serial data.
[0050]
The selection gate 34 is related to the selection means of the present invention and performs switching for sequentially driving the nozzles of the head 17 into two groups of odd and even numbers. The selection gate 34 has 128 AND gates in parallel, the output terminal of each digital comparator 33 is connected to one of the input terminals, and the other input terminal is connected to the control circuit. X and Y are selection signals for selectively using the nozzles of the head 17 for recording, and are output from the control circuit 23. In the present embodiment, the recording means is divided into two sets of odd-numbered and even-numbered using the selection signals X and Y, and alternately driven, that is, jetted. By this driving method, ink is ejected from the adjacent nozzle every time one pixel, that is, a maximum of 16 ink droplets is hit. This is because when the nozzles have different ejection characteristics, it takes into account the fact that all nozzles are used in succession, resulting in image streaks, etc. be able to. In this example, the odd-numbered and even-numbered two sets are used, but the nozzle head 17 may be divided into two or more sets.
[0051]
The level shifter 35 shifts the level of the drive signal, which is the output of the selection gate, from 0 necessary for driving the piezo to the power supply voltage.
[0052]
When the output of the level shifter 35 is in a Hi state, a drive signal is output from the driver 36. On the other hand, when the output of the level shifter 35 is in a low state, the drive signal is not output.
[0053]
The output terminal of the driver 36 is connected to a piezo element of each corresponding nozzle of the head 17. When a drive signal is given from the driver 36, ink is ejected by the piezo element of the connected nozzle and no drive signal is given. In this case, ink is not ejected by the piezo element of the nozzle connected to this terminal.
[0054]
FIG. 4 is a timing chart for explaining generation of a drive signal for performing ejection of all 16 gradations.
[0055]
The 4-bit counter 37 is a 4-bit up-counter that sequentially increases in response to the counter signal CNT, and outputs the count signals DC0 to 3 related to the count signal of the present invention. The count value is reset to 0 by the reset signal RST.
[0056]
The ejection signal CMP is an output of the digital comparator 33. The digital comparator 33 is set to output the ejection signal CMP as the Hi level when the image data value is greater than the count value, and to output the ejection signal CMP as the Low level when the image data value is equal to or less than the count value. FIG. 4 shows a waveform when the value of the image data is 7, for example.
[0057]
First, the digital comparator 33 compares the counter value 0 at CNT = 1 with the magnitude of the image data. When CNT = 1, since the image data value is 7 and the count value is 0, the image data is large, so that the ejection signal CMP outputs a Hi level signal. When the counter signal advances to 2, 3, 4,..., The count value increases to 1, 2, 3,. Since the condition that the counter signal = 7 and the count value = 6 and the image data value is larger than the count value is satisfied, the ejection signal CMP changes in the Hi level state until the counter signal CNT is 1-7. This Hi signal becomes a drive signal for gradation recording. Since the count value = 7 when the counter signal = 8 and the image data value is equal to or less than the count value, the ejection signal CMP transitions in a low state until the counter signal CNT is 8-15.
[0058]
As described above, by comparing the parallel 4-bit image data with the comparison means, 16 ejection signals from 0 ejection (no ejection) to 15 ejections are obtained, and one pixel is recorded in 16 gradations. To do.
[0059]
When a predetermined timing elapses from the 15th counter signal, the reset signal RST is output from the control circuit 23 to the 4-bit counter 37, and the count values DC0 to DC3 are reset. Further, the comparison relating to the first ejection signal is started by the reset signal RST.
[0060]
Note that the X and Y injection periods are switched by selection signals X and Y given to the selection gate 34.
[0061]
FIG. 5 is a timing chart in gradation recording when all 16 gradations are used.
[0062]
A square wave described as 0 gradation to 15 gradation indicates a drive signal generated in accordance with each gradation.
[0063]
As an example, it is assumed that the value of image data of one pixel latched by the latch 32 is zero. At this time, the density of this pixel is zero. When the digital comparator 33 compares the counter value 0 output when the CNT = 1 of the 4-bit counter 37 and the image data value 0, the output of the digital comparator 33 is low level because the image data value = counter value. Thereafter, even if CNT changes from 2 to 16, the image data value is less than the counter value, so that the output of the digital comparator 33 transitions with the Low level.
[0064]
If the output of the digital comparator 33 is Low, the drive signal is not output from the output terminal of the driver 36 by pulling the selection gate 34, so that ink is not ejected from the corresponding nozzle of the head 17.
[0065]
As a next example, it is assumed that the value of image data of one latched pixel is 7. At this time, when the digital comparator 33 compares CNT = 1 to CNT = 7, the image data value is larger than the counter value, so the output of the digital comparator 33 transitions at the Hi level. Thereafter, since the image data value is less than the counter value for CNT from 8 to 16, the output of the digital comparator 33 transitions with the Low level.
[0066]
If the output of the digital comparator 33 is Hi, the selection gate 34 and hence the level shifter 35 are Hi, so that a drive signal is output from the driver 36. Then, after CNT = 8, the output of the digital comparator 33 is at a low level, so that no drive signal is output from the output terminal of the driver 36. Therefore, the head 17 ejects only 7 drops of ink and records on the recording paper P.
[0067]
Although the above is a specific example, droplets corresponding to the drive signals of each gradation are ejected from the head 17 and gradation recording is performed. The ink droplets are sequentially recorded on the recording paper P, and recording of an area corresponding to the number of droplets becomes possible, and gradation recording is performed. Then, when the image data of the next pixel is latched from the shift register 31 to the latch 32, the LOAD signal rises again, and the Hi level according to the number of ink droplets in real time according to the comparison result between the value of the image data and the counter value. A drive signal whose period is changed is output.
[0068]
As described above, since the parallel signal is converted into the serial signal by the digital comparator 33 according to the comparison means of the present invention, the shift register 31 according to the first storage means of the present invention and the second storage means of the present invention are applied. The latch 32 can also be configured to handle 4-bit parallel data, and image data can be transferred from the control board 9 to the head driver 16 in parallel.
[0069]
Here, another embodiment will be described with reference to FIG.
[0070]
FIG. 6 is a modification of the head driver shown in FIG. FIG. 6 shows an example in which the second memory in FIG. 3 is omitted. The same numbers as those in FIG. 3 have the same configuration. Hereinafter, parts different from FIG. 3 will be described.
[0071]
In this figure, when the ink ejection operation by the head 17 is started, first, DATA0 to DATA3 are sequentially input to the first memory (128 bits × 4 shift register) in synchronization with CLKIN. When all 128 registers have been input, the CLKIN input is stopped and the register contents are fixed.
[0072]
In this state, the first memory is in the same state as the second memory described above. That is, each 4-bit register is sequentially compared with the outputs of the cant-up outputs D0 to D3 of the counter 37 and input to the selection gate. This period is the ink ejection period from the head.
[0073]
When the parallel-serial conversion of the data in the register is completed by the comparator, the data input to the first memory, that is, CLKIN is released, and the next data can be input.
[0074]
In this example, ink cannot be ejected from the head 17 during the period when data is input to the first memory, but the period during which this data is input, that is, the transfer time is sufficient compared to the ink ejection period. If it is short, almost the same effect can be expected without the second memory.
[0075]
FIG. 7 is a perspective view showing a main part of an example in which the present invention is applied to an ink jet printer 100 having a line head.
[0076]
The line head 117 has 128 nozzles per color arranged in the resin inner case 117Y, M, C, K along the main scanning direction, and further overlaps four in the sub scanning direction in the outer case 117a. I have paid. Similarly, the droplet ejection operation is controlled by the head driver 16 relating to the multi-tone printer driving apparatus of the present invention housed in the outer case 117a.
[0077]
Similar to the inkjet printer 1, the paper transport mechanism 8 transports the recording paper P in the sub-scanning direction by the transport motor 8a transport roller pair 8b and transport roller pair 8c. Other configurations of the control board 9, the integrated head driver 16, and the like are the same as those of the inkjet printer 1.
[0078]
The ink jet printer 100 transfers image data transferred from a personal computer or the like to the line memory 13 as in the ink jet printer 1, and the image data expressed in 4 bit gradation per pixel is connected from the line memory 13 by the flexible cable 5. To the head driver 16. When the trigger-in signal TRGIN is input, the head driver 16 performs recording on the recording paper P by ejecting ink from the nozzle head 17 in the same manner as the head driver 16 of the inkjet printer 1.
[0079]
FIG. 8 is a block diagram for explaining a main part of another example of the head driver according to the driving apparatus for the multi-tone printer of the present invention.
[0080]
The example of the head driver 16 is an example in which 4-bit gradation data constituting one pixel is sequentially transferred from the control board 9 by a 4-bit data signal line one by one. On the other hand, the head driver 116 is an example in which the lower order bits of the 4-bit gradation data of 128 pixels are sequentially transferred by the 128-bit data signal line. In addition, the same component as FIG. 3 is attached | subjected the same code | symbol.
[0081]
Gradation image data in which one pixel is composed of a plurality of bits, here 4 bits, is transferred from the line memory 13 sequentially in parallel from the lower bits. The block diagram of FIG. 8 shows a state in which the first 128-bit lower-order bit data DAT0 to DAT127 are transferred through a 128-bit data signal line.
[0082]
The shift register 131 has a capacity capable of storing image data of a number of pixels corresponding to one ejection by the nozzle head 17. Also in this embodiment, image data for 128 pixels arranged in the sub-scanning direction is stored. When the carriage 2 reaches a position suitable for recording, the control circuit 23 outputs a LOAD signal, and the latch 32 latches the image data output in parallel from the shift register 31 when receiving the LOAD signal.
[0083]
The latch 32 outputs image data to the digital comparator 33 in the same manner as the head driver 16. Since other operations of the head driver 116 are the same as those of the head driver 16, they are not specifically described here. The head driver 16 is an example of improving the transfer speed by the gradation per pixel, whereas the head driver 116 of this example is an example of improving the transfer speed by the number of nozzles of the nozzle head 17. It is.
[0084]
【The invention's effect】
As described above, since the parallel data having gradation information is transferred to the head driver as parallel data and processed by the printer according to the first aspect of the invention, multi-gradation recording can be performed at high speed. . In addition, parallel data having multiple gradations is compared by a comparison means and converted to serial data, thereby converting the number of droplets to be ejected and obtaining gradation recording, so that gradation recording can be performed at high speed.
[0085]
Further, by providing a gate at the output of the comparison means, it is possible to easily set ejection or non-ejection, and by selectively performing recording using the nozzle head, it is possible to prevent unevenness in each nozzle head.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a main part of an ink jet printer.
FIG. 2 is a circuit block diagram of the ink jet printer 1;
FIG. 3 is a block diagram of a head driver.
FIG. 4 is a timing chart for explaining generation of a drive signal for performing ejection of all 16 gradations.
FIG. 5 is a timing chart in gradation recording when all 16 gradations are set.
FIG. 6 is a block diagram of a head driver.
7 is a perspective view showing a main part of the ink jet printer 100. FIG.
FIG. 8 is a block diagram of a head driver.
[Explanation of symbols]
1 Inkjet printer
2 Carriage
3 heads
5 Flexible cable
7 Encoder
9 Control board
11 CPU
12 page memory
13 line memory
14 Interface
15 Drive waveform generation circuit
16 Head driver
17 heads
19 Thermistor
23 Control circuit
31 Shift register
32 Latch
33 Digital comparator
34 Selection gate
35 level shifter
36 drivers
37 counter

Claims (5)

Each pixel is composed of a plurality of bits indicating gradation, the plurality of bits of data are inputted in parallel, the pixel data is sequentially stored for each pixel, and after storing a predetermined number of pixel data, the stored pixel data First storage means for outputting in parallel;
Counting means for generating a counter signal;
A plurality of comparisons provided corresponding to the respective outputs of the first storage means and comparing each pixel data of the first storage means with the counter signal and outputting a drive signal according to the comparison result Means,
And recording means for said provided corresponding to the respective comparing means, and is driven based on the changed driving voltage according to a drive signal from the respective comparator means,
A printer driving apparatus comprising: a selecting unit for selecting an output of the comparing unit and causing a desired recording unit to perform recording . Each pixel is composed of a plurality of bits indicating gradation, the plurality of bits of data are inputted in parallel, the pixel data is sequentially stored for each pixel, and after storing a predetermined number of pixel data, the stored pixel data First storage means for outputting in parallel;
Second storage means for outputting in parallel the first recording means latches the pixel data outputted in parallel,
Counting means for generating a counter signal;
Provided corresponding to respective outputs of said second storage means, and a plurality of comparison for comparing the respective pixel data and the counter signal, and outputs a drive signal according to the comparison result of said second storage means Means,
And recording means for said provided corresponding to the respective comparing means, and is driven based on the changed driving voltage according to a drive signal from the respective comparator means,
A printer driving apparatus comprising: a selecting unit for selecting an output of the comparing unit and causing a desired recording unit to perform recording . Each pixel is composed of a plurality of bits indicating gradation, and the data of the plurality of pixels is sequentially input in parallel from the lower bits or the upper bits of the plurality of bits to sequentially store the pixel data, and a predetermined number of pixel data is stored. A first storage means for outputting the stored pixel data in parallel;
Second storage means for said first recording means outputs in parallel the latched pixel data outputted in parallel,
Counting means for generating a counter signal;
A plurality of comparisons provided corresponding to the outputs of the second storage means and comparing each pixel data of the second storage means with the counter signal and outputting a drive signal according to the comparison result Means,
And recording means for said provided corresponding to the respective comparing means, and is driven based on the changed driving voltage according to a drive signal from the respective comparator means,
A printer driving apparatus comprising: a selecting unit for selecting an output of the comparing unit and causing a desired recording unit to perform recording . Each pixel is composed of a plurality of bits indicating gradation, the plurality of bits of data are inputted in parallel, the pixel data is sequentially stored for each pixel, and after storing a predetermined number of pixel data, the stored pixel data First storage means for outputting in parallel;
Counting means for generating a counter signal;
A plurality of comparisons provided corresponding to the respective outputs of the first storage means and comparing each pixel data of the first storage means with the counter signal and outputting a drive signal according to the comparison result Means,
A recording means provided corresponding to each comparison means and driven based on a drive voltage changed according to a drive signal from each comparison means;
Selecting means for selecting the output of the comparing means, and causing recording to be performed by a desired recording means among the recording means;
A carriage that includes the first storage unit, the comparison unit, the recording unit , and the selection unit, and is held movably during recording;
A printer comprising data transfer means for transferring data between the carriage and a substrate provided in a printer body, and having flexibility and following movement of the carriage. Each pixel is composed of a plurality of bits indicating gradation, the plurality of bits of data are inputted in parallel, the pixel data is sequentially stored for each pixel, and after storing a predetermined number of pixel data, the stored pixel data First storage means for outputting in parallel;
Second storage means for latching and outputting in parallel the pixel data output in parallel by the first storage means;
Counting means for generating a counter signal;
A plurality of comparisons provided corresponding to the outputs of the second storage means and comparing each pixel data of the second storage means with the counter signal and outputting a drive signal according to the comparison result Means,
A recording means provided corresponding to each comparison means and driven based on a drive voltage changed according to a drive signal from each comparison means;
Selecting means for selecting the output of the comparing means, and causing recording to be performed by a desired recording means among the recording means;
A carriage that includes the first storage unit, the second storage unit, the comparison unit, the recording unit , and the selection unit, and is held movably during recording;
A printer comprising data transfer means for transferring data between the carriage and a substrate provided in a printer body, and having flexibility and following movement of the carriage.

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