JP2812464B2 - Ink jet recording device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus, and more particularly, to an on-demand type ink jet that ejects ink to a recording medium in response to a drive signal when an image such as a character or a figure is formed. It relates to a recording device. [Prior Art] FIG. 8 shows an example of this type of conventional ink jet printer. Here, 101 is a platen roller that conveys the recording medium in the sub-scanning direction in accordance with the drive of the line feed motor 107 and regulates the recording surface. Reference numeral 102 denotes an ink jet recording head which reciprocates in a direction (main scanning direction) indicated by an arrow S in the figure according to the driving of the carriage motor 108, and discharges ink to a recording medium in the process to perform recording.
For example, a printer capable of performing multi-color recording may have a nozzle group of yellow, magenta, cyan, and black corresponding to the ink color as shown in the figure. Reference numeral 103 denotes a cap member disposed opposite to the head 102 at, for example, a home position outside the recording range of the head 102, and moves in the F direction in the figure according to the driving of the cap motor 106 when the printer is not used. To the head 102 for protection and the like. 104 is a photo sensor that moves in the S direction integrally with the head 102, and is a linear encoder arranged in parallel with the S direction.
The movement position of the head 102 is detected in cooperation with 105. Further, 109 is a paper sensor for detecting the recording medium, 110 is a cap sensor for detecting the position of the cap 103, and 111 is a head sensor.
It is a home position sensor that detects the positioning of 102 in the home position. In such a conventional inkjet printer,
The printing medium is fed in the sub-scanning direction by the platen 101 in response to the driving of the line feed motor 107, and printing starts when the paper sensor 109 detects the printing medium. At this time, first, the cap motor 106 operates, and the cap 103 is moved to the head 10.
Remove from 2. When the cap sensor 110 detects this, the carriage motor 108 operates, and the head 102 moves in the main scanning direction S. Then, the sensor 104 and the encoder 1
The head position is detected in cooperation with 05, and the head 102 discharges ink according to the ink discharge timing signal. In such an ink jet recording apparatus, a head
The 102 has a large number of nozzles, and whether or not all the nozzles are used at the time of printing is uncertain depending on the shape and color of the image to be formed. Rather, in many cases, one of the nozzles is not used. By the way, one of the problems to be solved in the on-demand type ink jet recording apparatus is that the nozzle is easily clogged if it is not used for a long time, or even if it is not used for a long time before it is clogged. When the ink is used, normal ejection may not be performed due to the increase in the viscosity of the ink, so that the recording quality may be deteriorated. Therefore, an ink collecting member is provided on the cap member 103,
Start the timer during printing, and when the non-printing state exceeds the set time, move the head and drive all nozzles toward the ink collection member to eject ink (preliminary ejection)
There are things that let me do that. Further, there is a type in which ink is sucked from a nozzle by a suction unit provided on the ink collecting member side, and a type in which ink is discharged from the nozzle by a pressurizing unit provided in an ink supply system. In order to improve the recording quality, it is most preferable to always use the nozzles. Therefore, the above operation (hereinafter, referred to as an ejection recovery process) needs to be performed frequently. [Problems to be Solved by the Invention] However, although the amount of ink used at one time in the above-described forced ejection or preliminary ejection in the ink jet recording apparatus is small, it is necessary to perform a large number of inks, so that the ink is consumed here. The amount of ink used is enormous. In addition, in the on-demand type ink jet recording method, since the ink cannot be reused, there is a problem that all the ink consumed here is wasted and the running cost of the ink is reduced. On the other hand, it is needless to say that it is desirable that the printing and the formed image by the recording device be beautiful and fine. For this purpose, among the ink jet recording heads, a bubble jet type which has an electrothermal transducer as a discharge energy generating element and heats and foams the ink by energizing the element, and discharges the ink with that force. Recording head (hereinafter BJ
The head is preferable because nozzles can be closely arranged due to its configuration, and high-density recording can be performed without performing staggered arrangement. However, with the increase in the density of such nozzles, the above problem becomes more significant. FIG. 2 and FIG. 3 of Japanese Patent Application Laid-Open No. 56-155405 show in this regard that the printing signal is monitored by a counter provided for each nozzle, and the printing signal is monitored within a set time. A recording apparatus is disclosed in which when a missing nozzle occurs, only a nozzle having no print signal is idle-sprayed. However, although the waste of ink in the ejection recovery processing is reduced, the circuit scale increases because a counter is provided for each nozzle. That is, this problem becomes more remarkable as the number of nozzles increases. SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet recording apparatus which solves the above problem and minimizes the waste of ink in the ejection recovery processing without increasing the circuit scale. [Means for Solving the Problems] For this purpose, the present invention provides an ink jet recording apparatus which has a plurality of nozzles for discharging ink and controls recording by an MPU, and is provided corresponding to each of the plurality of nozzles. A plurality of latch circuits reset based on a command of the MPU, wherein print data supplied for ink ejection from each nozzle is input corresponding to each of the plurality of nozzles, and the MPU And a plurality of latch circuits that hold non-use data indicating that ink is not ejected from the corresponding nozzle during a period until reset by the MPU. Control means for causing the corresponding nozzle to perform preliminary ejection based on the use data. [Operation] According to the present invention, it is possible to perform preliminary ejection only from unused nozzles based on use / non-use information for each nozzle during ejection recovery processing after printing of a predetermined amount, and to reduce ink consumption. The amount can be reduced. Further, since the information is stored in a latch circuit, the circuit scale does not increase. Further, since the information is latched in accordance with the driving of the recording head at the time of recording, the control element such as a microcomputer is used by software. Management becomes unnecessary, and the burden can be reduced. [Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings. (Embodiment 1) FIG. 1 shows a first embodiment of the present invention. In the figure, reference numeral 1 denotes an input buffer for recording data supplied from a host device (not shown) as a recording data supply source via a main control unit (not shown) of the device connected to the data buses D0 to D7, and 2 denotes a host device. And 3 are input buffers for reference signals from the host device. Reference numeral 4 denotes a status controller for converting a status signal into a control signal, and reference numeral 5 denotes a command register for storing command data for controlling the operation of the circuit according to the present embodiment. Reference numeral 6 denotes a bit inverter capable of inverting the LSB to MSB of 8-bit data in units of bits or in units of bytes to “white” or invert a character,
Of course, non-inversion is also possible. Reference numeral 7 denotes a print data latch controller that performs control when latching print data, 8 denotes a heat controller that controls timing when print data is output, and 9 to 14.
Denotes a print data latch unit for storing print data for eight nozzles, and 15 to 20 denote print data latch units 9 to
This is an output control circuit that controls and outputs the recording data stored in 14 by the heat controller. Reference numerals 21 to 26 denote output buffers for amplifying signals from the output control circuits 15 to 20 for output, and reference numeral 27 denotes an output buffer for amplifying a signal indicating that the circuit according to the present embodiment is operating. Reference numerals 28 to 33 denote output data latch units for monitoring the output of print data and storing unused nozzles. The output data latch control unit 34 outputs information on unused nozzles. The output data latch control device 34
That is, for example, the data of the unused nozzles stored in the output data latch units 28 to 33 is output in response to a request from the main control unit described later with reference to FIG. 35 is an output buffer that receives information on unused nozzles from the output data latch units 28 to 33,
These buffers are output to the data buses D0 to D7. FIG. 2 is a specific configuration example of the output data latch units 28 to 33 shown in FIG. In the figure, a reset signal ▼ from the main control unit is commonly input to a clear terminal ▼, output data D0 to D7 are input to a clock terminal C, and a reference potential Vcc is input to a data input terminal D. doing. Therefore, when the output data is input, that is, when the nozzle is used, the reference potential (“1”) is latched by the output data, and “1” is output from the data output terminal Q and is not used. In this case, "0" is output.
In this example, the D-type flip-flop is configured with eight D-type flip-flops and a three-state buffer, and stores information on unused nozzles. Further, the control unit 34 transfers information of the unused nozzles to the data bus D0 by the control unit 34.
Used to output to ~ D7. FIG. 3 shows a specific configuration example of the output data latch control device 34 shown in FIG. In this example, for example, a decoder corresponding to 74LS138 manufactured by Texas Instruments and an AND gate are provided. This device performs control of sequentially outputting information on the used nozzles from the latch units 28 to 33 to the data buses D0 to D7 and control of the reset operation of the latch units 28 to 33. Next, the operation of the first embodiment will be described step by step. [At power-on] When a reset signal ▼ is input from the main control unit at power-on, this signal is transmitted to the command register 5, the recording data latch controller 7 and the heat controller 8 via the input buffer 3. At this time, the command data recorded in the command register 5 is cleared, and the recording data latch controller 7 clears the recording data stored in the print data latch units 9 to 14. Further, the heat controller 8 prohibits and stops the print data output. Further, the output data latch control device 34 clears the storage contents of the latches of the output data latch units 28 to 33. Thus, the operation at the time of turning on the power is completed. [At the time of command setting] Control at the time of command data setting is performed by the signals RS0 to RS3 and ▲.
The command data is transmitted through the data buses D0 to D7. In this example, the command setting operation is RS0 = 1, RS3 = 0, ▲
This is performed when ▼ = 0 and ▲ = 0, and is performed by controlling the command register 5 via the input buffer 2 and the status controller 4. In other words, the host device outputs the heat pulse width, barium, LSB-MSB inversion / non-inversion (inversion / non-inversion of character image) of recording data bit, and LSB of recording data byte unit.
Setting data such as inversion / non-inversion of MSB (character inversion / erecting) and a heat order are output to data buses D0 to D7 and set in command register 5 via input buffer 1. [Record data setting] The control for setting the record data is performed by the signals RS0 to RS3, ▲ ▼,
The recording data is transmitted through the buses D0 to D7. In this example, the recording data setting operation is RS = 0, RS3 = 0, ▲
Performed when ▼ = 0, ▲ ▼ = 0, input buffer 2
This is performed by controlling the recording data latch controller 7 via the status controller 4. In accordance with the setting data for inversion / non-inversion of LSB to MSB in units of bits and inversion / non-inversion in units of bytes stored in the command register 5, recording data supplied from the host device via D0 to D7 is input. The data is stored in the designated recording data latch unit among the recording data latch units 9 to 14 under the control of the recording data latch controller 7 via the buffer 1 and the bit inverter 6. [Output of Print Data] There are two modes for outputting the print data latched as described above. One is to start the output operation by the signal TOI, and the other is to start the signal RS, ▲ ▼, ▲
▼ starts the output operation. When one of these two output start signals is input,
The heat controller 8 operates to operate the output control circuits 15 to 20, and output the recording data latched by the recording data latch units 9 to 14 via the output buffers 21 to 26. At this time, a signal TOO indicating that the circuit according to the present example is operating is output from the heat controller 8 and output to, for example, a host device via the output buffer 27. [Output Storage of Print Data] When print data is output, the output data latch units 28 to 33 store information on unused nozzles based on output data of the output control devices 15 to 20. This data is held until cleared by the output data latch control unit 34. When the information of unused nozzles stored in the output data latch units 28 to 33 is ▲ = 0, ▼ = 0, and RS3 = 1, three bits of RS0 to 2 are used for information of unused bytes of 6 bytes. And select
By the output data control device 34, output as needed,
The data is output to the data buses D0 to D7 via the output buffer 35. The MPU may monitor the information on the unused nozzles, for example, in units of one line (one main scan), and perform control to preliminarily discharge only the unused nozzles during one line. That is, since the unused nozzle information is represented by “0”, the MPU controls the preliminary ejection by inverting the information using the bit inverter 6 and then causing the print data latch units 9 to 14 to latch the information. After this ▲
The control unit 34 outputs a signal for resetting the information of the unused nozzles stored in the latch units 28 to 33 in accordance with the signals ▼ = 0, ▼ = 0, and RS3 to RS0 = 1. This preliminary ejection can be performed, for example, by the following means and processing procedure. FIG. 4 shows an example of the configuration of a control system for performing preliminary ejection. In this example, the control system is also used as a main control unit of an ink jet printer. Here, reference numeral 300 denotes an MP in the form of, for example, a microprocessor for controlling each unit according to the processing procedure shown in FIG.
Reference numerals U and 303 denote interface units for controlling transmission and reception of image data and control signals for recording with the external host device H. A buffer memory unit 307 temporarily stores image data transferred from the host device H. Reference numeral 306 denotes a cap drive unit coupled to the cap system 206 including the cap 103, the cap motor 106, and the cap sensor 110 shown in FIG.
By controlling the driving of the cap motor 106 based on the position information detected by the sensor 110 via the 306, the cap 103
The recording head 102 is opened and closed. Reference numeral 301 denotes a paper feed drive unit coupled to a paper feed system 201 including a plantain roller 101, a line feed motor 107, a paper sensor 109, and the like. The MPU 300 controls the conveyance of the recording medium via the paper feed system drive unit 301. I do. 304 is a carriage on which the recording head 102 shown in FIG.
This is a main scanning system drive unit coupled to a main scanning system including a carriage motor 108, a photo sensor 104, and the like. The MPU 300 controls scanning in the S direction in FIG. 302
Is a first illustrated control circuit for driving the recording head 102. Reference numeral 308 denotes a ROM storing programs and the like corresponding to the processing procedure described later with reference to FIG. 5, and reference numeral 309 denotes a RAM used for work. Reference numeral 310 denotes a bus line that collects an address bus, a control bus, and a data bus (D0 to D7) connecting the above-described units 300 to 304 and 307 to 309. FIG. 5 shows an example of a preliminary ejection processing procedure by the control system shown in FIG. First, when printing is performed at one position in the main scanning direction (S direction) while driving the main scanning system 204 in step S1, it is determined in step S3 whether one main scan is completed. If the determination is negative, the process returns to step S1 to continue recording. On the other hand, if the determination is affirmative, the process proceeds to step S5, where the recording head 102 is moved to the home position and the cap 1
Make it face 03. At this time, the paper feed system 201 may be driven to perform line feed. In step S7, the cap system 306 is driven to
Is connected to the recording head 102, and then, in step S9, the above-mentioned status is sent to the control circuit 302 shown in FIG. In step S11, based on the information, only the ejection energy generating element corresponding to the unused nozzle in the main scanning is driven to perform the preliminary ejection. When the preliminary ejection is completed, the process proceeds to step S13, and the cap 103 is opened in preparation for the next scan. Step S
At 15, the status is sent to the control circuit 302 to clear the data stored in the output data latch units 28 to 33. According to the present embodiment, since the ejection recovery process is performed by performing the preliminary ejection only from the unused nozzles, the amount of ink consumption in the process can be reduced. In addition, if the control of the use / non-use nozzles of the print head is performed by a control element such as an MPU, the printing speed is limited by the processing speed of the control element such as the MPU.
By storing the used / unused nozzles of the print head in the print control circuit, the effect of reducing the load on the control element such as the MPU was also obtained. This eliminates the need to use a control element such as an effective high-speed MPU even when the recording speed is increased, and thus leads to a reduction in the cost of an ink jet printer using the control circuit according to the present embodiment.
Note that the timing of the preliminary ejection can be determined arbitrarily and not only at the end of one main scan as described above. For example, it may be performed for each of a plurality of scans or at the end of recording of one page. (Embodiment 2) Fig. 6 shows another embodiment of the present invention. Here, the same reference numerals are given to the corresponding parts of the same configuration as those of Fig. 1, and the description is omitted. In the figure, reference numeral 80 denotes a heat controller for controlling the timing of outputting print data, and 65 to 70 output print data stored in the print data latch units 9 to 14 under the control of the heat controller 80. And an output control circuit for driving only the nozzles that have not performed print output during the ejection recovery process. FIG. 7 is a specific configuration example of the output control circuits 15 to 20 in FIG. In this example, the D-type flip-flop is configured with eight D-type flip-flops and a 3-state buffer, and stores information on nozzles not used by the D-type flip-flops. A portion 80A within the broken line in FIG. 7 is a circuit for resetting the flip-flop and switching between the output of the non-use information of the nozzle and the output of the recording data. This circuit may be provided in the heat controller 80. it can. Here, since the non-use information is obtained as the output of the data output terminal ▼ of the flip-flop, “1” is output when the nozzle is not used. Next, the operation of the first embodiment will be described step by step. [At power-on] When a reset signal ▼ is input from the main control unit at power-on, this signal is transmitted to the command register 5, the recording data latch controller 7 and the heat controller 8 via the input buffer 3. At this time, the command data stored in the command register 5 is cleared, and the print data latch controller 7 clears the print data stored in the print data latch units 9 to 14. Further, the heat controller 8 resets the storage latches of the unused nozzles incorporated in the output control circuits 15 to 20, and inhibits and stops the print data output. Thus, the operation at the time of turning on the power is completed. [At the time of command setting] Control at the time of command data setting is performed by signals RS0, RS1,
The command data is transmitted through the data buses D0 to D7. In this example, the command setting operation is RS0 = 1, RS1 = 1, ▲
This is performed when ▼ = 0 and ▲ = 0, and is performed by controlling the command register 5 via the input buffer 2 and the status controller 4. That is, the host device sets the heat pulse width at the time of output, inversion / non-inversion of LSB to MSB in units of recording data, LSB to MSB inversion / non-inversion of bytes of recording data, and setting data such as heat order. Are output to the data buses D0 to D7 and set in the command register 5 via the input buffer 1. [Recording data setting] Control for setting recording data is performed by signals RS0, RS1, ▲ ▼, ▲
The recording data is transmitted via the buses D0 to D7. In this example, the recording data setting operation is RS0 = 0, RS1 = 0, ▲
Performed when ▼ = 0, ▲ ▼ = 0, input buffer 2
This is performed by controlling the recording data latch controller 7 via the status controller 4. In accordance with the setting data for inversion / non-inversion of LSB to MSB in units of bits and inversion / non-inversion in units of bytes stored in the command register 5, recording data supplied from the host device via D0 to D7 is input. The data is stored in the designated recording data latch unit among the recording data latch units 9 to 14 under the control of the recording data latch controller 7 via the buffer 1 and the bit inverter 6. [Output of Print Data] There are two modes for outputting the print data latched as described above. One starts the output operation by the signal TOI, and the other starts the signals RS0, RS1, ▲ ▼, ▲.
▼ starts the output operation. When one of these two output start signals is input,
The heat controller 8 operates to operate the output control circuits 15 to 20, and outputs the data via the recording data output buffers 21 to 26 latched by the recording data latch units 9 to 14. At this time, a signal TOO indicating that the circuit according to the present example is operating is output from the heat controller 8 and, via the output buffer 27,
For example, it is output to the host device. [Output Storage of Print Data] When print data is output, information on unused nozzles is stored in flip-flop groups provided in the output control devices 15 to 20, respectively. This recording data latch is held until cleared by the heat controller 80. [Output to Unused Nozzle] When outputting to an unused nozzle, the MPU or the like sets the SEL signal of FIG. 7 to “H” via the heat controller 80 and outputs an output operation start signal (all If a signal for operating the nozzles) is transmitted to the control circuit shown in FIG. 6 in the same manner as during normal printing, output can be performed only to unused nozzles by the circuit shown in FIG. Such preliminary ejection can be performed by a control system shown in FIG. 4 or a processing procedure similar to that shown in FIG. For example, when performing preliminary ejection to an unused nozzle during one page, the following may be performed. That is, the MPU 300 changes step S3 in FIG. 5 so as to move to the carriage home position on which the recording head 102 is mounted at the end of the recording operation in one page, and immediately after step S7, sets the SEL signal to “H”. An output operation start signal is transmitted to the circuit according to the present embodiment with an appropriate heat pulse, and preliminary ejection is performed. And
When the preliminary ejection is completed, after step S13, the SEL signal is returned to "L" to set the normal print mode, and the latch of the unused nozzle (the D-type flip-flop group shown in FIG. 7) may be cleared. Will be. According to this example, the same effect as that of (Example 1) can be obtained. In addition, as compared with the case where the MPU 300 checks the information of the unused nozzles once and then performs the operation such as the preliminary ejection (Embodiment 1), the normal print output and the unused nozzle output at the time of the ejection recovery processing are simply compared with each other. Since the recording output operation start signal may be transmitted by switching to the two modes, the procedure of reading the unused nozzle information can be omitted, and the load on the MPU 300 can be further reduced. In the above two examples, the case where the present invention is applied to a serial type ink jet printer that performs printing by mounting a print head on a carriage and performing main scanning has been described. However, nozzles are arranged over the entire width of a print medium. Needless to say, the present invention can be applied very effectively and easily to an ink jet printer of a line printer type having a so-called full multi-type recording head. [Effects of the Invention] As described above, according to the present invention, it is easy to discharge only the unused nozzles within a certain period. That is, for example, if the present invention is applied to a control circuit of a print head of a serial printer, preliminary discharge of only the upper and lower nozzles of the print head which is hardly used in the serial printer can be performed, and the discharge can be performed without consuming unnecessary ink. It is possible to prevent defects. According to the measurement by the present applicant, it has been confirmed that the amount of ink consumed in the preliminary ejection is 1/3 or less. This indicates that the on-demand type print head has an effect of greatly reducing the amount of waste ink. In addition, since the life of the BJ head is liable to abrasion failure, the present invention performs preliminary discharge only for unused nozzles instead of uniformly performing preliminary discharge as in the related art.
The effect of increasing the life of the BJ head by suppressing the variation in the frequency of use for each nozzle was also obtained. Furthermore, compared to a method in which an unused nozzle is processed by an MPU or the like, it is used in accordance with print data for ejection recovery processing.
Since it is not necessary to increase the processing such as managing the unused data, the load on the MPU or the like is reduced, and the effect that high-speed recording is enabled is obtained. In addition, the present invention makes it easy to form a gate array,
It can be provided small and inexpensive.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention, FIG. 2 is a circuit diagram showing a configuration example of an output data latch unit in FIG. 1, and FIG. 1 is a circuit diagram showing a configuration example of the output data latch control device in FIG. 1, FIG. 4 is a block diagram showing a configuration example of a control system for preliminary ejection using the circuit shown in FIG. 1, and FIG. FIG. 6 is a block diagram showing a second embodiment of the present invention, and FIG. 7 is a circuit diagram showing an example of the configuration of an output data latch unit in FIG. FIG. 8 is a plan view showing an example of an ink jet printer to which the present invention can be applied. 1-3 Input buffer, 4 Status controller, 5 Command register, 6 Bit inverter, 7 Print data latch controller, 8 Heat controller, 9-14 Print data latch section 15-20, 65-70 output control circuit, 21-27,35 output buffer, 28-33 output data latch section, 34 output data latch control device, 102 print head, 206 …… Cap type, 300 …… MPU.

Claims (1)

(57) [Claims] An inkjet recording apparatus having a plurality of nozzles for discharging ink and controlling recording by an MPU, wherein the inkjet recording apparatus is provided corresponding to each of the plurality of nozzles,
A plurality of latch circuits reset based on a command of the MPU, wherein print data supplied for ink ejection from each nozzle is input corresponding to each of the plurality of nozzles, and is reset by the MPU. A plurality of latch circuits that hold non-use data indicating that ink is not ejected from the corresponding nozzle during a period until the non-use data held in the plurality of latch circuits is instructed by the MPU. And a control unit for performing a preliminary discharge to a corresponding nozzle on the basis of the information. 2. The control means, wherein the MPU reads non-use data held in the plurality of latch circuits, and the MPU causes the plurality of nozzles to perform preliminary ejection based on the read non-use data. The inkjet recording apparatus according to claim 1, wherein 3. The control means includes a selection circuit that switches non-use data held in the plurality of latch circuits to the print data and supplies the data as data for supplying ink from the plurality of nozzles. Range 1
Item 6. The ink jet recording apparatus according to item 1. 4. Each of the plurality of latch circuits has the clear terminal
2. The ink jet printing apparatus according to claim 1, wherein a reset command of the MPU is input, the print data is input to a nozzle corresponding to a clock terminal, and a reference potential is input to a data input terminal. .