JPH01127362A - Control circuit of recording head - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control circuit for an inkjet recording head, and in particular to an on-demand recording head that jets ink onto a recording medium in accordance with a drive signal when forming an image such as a single character figure. This invention relates to a control circuit for a type of inkjet recording head.

[Prior Art 1] FIG. 8 shows an example of this type of conventional inkjet printer.

Here, 101 is a platen roller that conveys the recording medium in the sub-scanning direction according to the drive of the line feed motor 107 and regulates the recording surface.

Reference numeral 102 denotes an inkjet recording head that moves back and forth in the direction shown by arrow S in the figure (main scanning direction) in response to the drive of the carriage motor 108, and performs recording by ejecting ink onto the recording medium in the process. A printer capable of color recording may have, for example, yellow, magenta, cyan, and black nozzle groups corresponding to the ink colors as shown in the figure. 103 is head 1
This is a cap member disposed facing the head 102 outside the recording range by 02, for example at the home position, and when the printer is not in use, the cap motor 10
6 moves in the direction f in the figure, and joins to the head 102 to protect it.

A photosensor 104 moves in the S direction together with the head 102, and detects the moving position of the head 102 in cooperation with a linear encoder 105 arranged parallel to the S direction.

Further, 109 is a paper sensor that detects a recording medium, and 110
is a cap sensor that detects the position of the cap 103;
A home position sensor 111 detects the positioning of the head 102 at the home position.

In such a conventional inkjet printer, the platen 1 is moved in response to the drive of the line feed motor 10.7.
01, the recording medium is sent in the sub-scanning direction, and the paper sensor 1
When 09 detects a recording medium, it starts printing. At this time, the cap motor 106 operates first, and the cap 1
03 is removed from the head 102. When the cap sensor 110 detects this, the carriage motor 108 operates, and the head 102 moves in the main scanning direction S. The head position is detected through cooperation between the sensor 104 and the encoder 105, and the head 102 ejects ink in accordance with the ink ejection timing signal.

In such an inkjet recording device, the head 1
02 is provided with a large number of nozzles, and whether or not all the nozzles are used during recording is uncertain depending on the shape and color of the image to be formed.

Rather, there are many cases where one of the nozzles is not used.

By the way, one of the problems that needs to be solved with on-demand type inkjet recording devices is that the nozzles tend to clog if they are not used for a long time, or even if the nozzles do not clog, they suddenly clog after a long period of non-use. If ink is used, normal ejection may not be performed due to increased viscosity of the ink, resulting in a decrease in recording quality.

Therefore, an ink collecting member is provided in the cap member 103,
A timer is started during printing, and when the non-recording state exceeds a set time, the head is moved and all nozzles are driven toward the ink collection member to eject ink (preliminary ejection).
There is something that lets you do it. In addition, there are some devices in which ink is sucked from the nozzle by a suction device provided on the ink collecting member side, and ink is discharged from the nozzle by a pressure device provided in the ink supply system.

In order to improve the recording quality, it is most desirable to use the nozzle all the time, so the above operation (
(hereinafter referred to as ejection recovery processing) 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-mentioned forced ejection and preliminary ejection in an inkjet recording device is small, it is necessary to perform many ink discharges, so ink is consumed here. The amount of ink used is enormous. In the on-demand type inkjet recording method, since ink cannot be reused, all the ink consumed here is wasted, resulting in a reduction in ink running costs.

On the other hand, it goes without saying that it is desirable that the print and formed images by the recording device be beautiful and precise. For this purpose, an inkjet recording head has an electrothermal converter as an ejection energy generating element, and by energizing it, the ink is heated and foamed, and the ink is ejected using that force. Bubble jet recording head (hereinafter referred to as B)
The J head) is suitable because its structure allows the nozzles to be closely arranged, and high-density recording is possible without staggered arrangement. However, as the density of such nozzles increases, the above-mentioned problems become more prominent.

SUMMARY OF THE INVENTION An object of the present invention is to provide a print head control circuit that can solve these problems and minimize ink waste during ejection recovery processing.

[Means for Solving the Problems] To this end, the present invention provides a control circuit for an on-demand recording head having a plurality of nozzles for ejecting ink, which is provided for each of the plurality of nozzles. The apparatus is characterized in that it includes a latch means for latching information indicating that the nozzle is not used in accordance with the driving of the recording head.

[Function 1] According to the present invention, during ejection recovery processing after recording a predetermined amount,
Based on the usage/non-use information for each nozzle, preliminary ejection can be performed only from unused nozzles, and ink consumption can be reduced.

Furthermore, since the information is latched in accordance with the driving of the recording head during recording, it is not necessary to manage whether or not the information is used by software of a control element such as a microcomputer, and the burden thereof can be reduced.

[Embodiment 1] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Example 1) FIG. 1 shows a first embodiment of the invention.

In the figure, 1 is a manual 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 a device coupled to data buses DO to D7, and 2 is a manual buffer for the host device. 3 is a human buffer for each status signal from the host device, and 3 is a human buffer for the reference signal from the host device.

4 is a status controller that converts a status signal into a control signal, and 5 is a command register that stores command data that controls the operation of the circuit according to this example. 6 is 8
This is a bit inverter that can completely invert the LSB to MSB of bit data bit by bit or byte by byte to make a character "white out" or upside down. Of course, it can also be used without inverting. It is possible.

7 is a recording data latch controller that controls when recording data is latched; 8 is a heat controller that controls timing when outputting recording data; 9 to 14;
15 to 20 are output control circuits which output the recording data stored in the recording data latch units 9 to 14 under the control of the heat controller.

Reference numerals 21 to 26 are output buffers for amplifying signals from the output control circuits 15 to 20 for output, and 27 is an output buffer for amplifying for output a signal indicating that the circuit according to this example is in operation.

Reference numerals 28 to 33 are output data latch units that monitor the output of recording data and store unused nozzles, and output information about unused nozzles by an output data latch control device 34. The output data latch control device 34 outputs the data of unused nozzles stored in the output data latch sections 28 to 33 as needed, that is, for example, in response to a request from a main control section described later with reference to FIG. 35 is an output buffer that outputs information on unused nozzles to a data latch unit 28 to
33 and outputs to data buses DO to D7.

FIG. 2 shows a specific example of the configuration of the output data latch sections 28 to 33 shown in FIG. In this example, it is composed of eight D-type flip-flops, a 3-state buffer, etc., and the D-type flip-flop stores information about unused nozzles. Also 3
The state buffer is used by the control device 34 to output information about unused nozzles to data buses DO to D7.

FIG. 3 shows a specific example of the configuration of the output data latch control device 34 shown in FIG. In this example, for example, a decoder equivalent to 74LSI38 manufactured by Texas Instruments and an AND
It consists of a gate. This device has latch parts 28 to
33 to the data bus DO-D7.
It performs control of output toward the latches 28 to 33 and control of reset operations of the latch sections 28 to 33.

Next, the operation of (Embodiment 1) will be explained step by step." [At power-on] When a reset signal is input from the main control section at power-on, this signal is sent to the command register 5 via the manual buffer 3. ．． The recorded data is transmitted to the latch controller 7 and the heat controller 8. At this time, the command data stored in the command register 5 is cleared, and the recording data latch controller 7 also clears the recording data stored in the print data latch units 9 to 14.

Further, the heat controller 8 prohibits and stops the output of recorded data. Further, the output data latch control device 34 clears the stored contents of the latches of the output data latch sections 28 to 33.

This completes the power-on operation.

[When setting a command] Control when setting command data is by signals R5O to R5:l
.

This is performed by WR and C5, and command data is transmitted via data buses DO to D7.

In this example, the command setting operation is R5O=1, R5
3=0. This is performed when ①=o and saku=o, 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 controls the heat pulse width at the time of output, the inversion/non-inversion of the LSB-MSB in units of hits of recorded data (inversion/non-inversion of character images), and the LS of recorded data in units of bytes.
B~MSB inversion/non-inversion (character inverted/upright)
etc., setting data such as heat order etc. are sent to data buses DO~D.
7 and is set in the command register 5 via the input buffer 1.

[Record data setting code] Control when setting recording data is by signals R50-R53, ■.

The recording data is transmitted via the bus Do-o7.

In this example, the recording data setting operation is R5=0, R5
3=O, WTI=o, C3=O (D toki Z is performed by controlling the recording data latch controller 7 via the manual buffer 2 and the status controller 4. LSD-MSB inversion/non-inversion and byte unit inversion/
Depending on the non-inverted setting data, ・DO- from the host device
The recording data supplied via 07 is input to input buffer 1.
The data is then stored in a designated recording data latch section of the recording data latch sections 9 to 14 under the control of the recording data latch controller 7 via the bit inverter 6 .

[Output of Recorded Data] There are two ways to output the recorded data latched as described above. One type starts the output operation based on the signal TOI, and the other type starts the output operation based on the signals R5, RD, and C5.

When either of these two output start signals is input manually, the heat controller 8 is activated and the output control circuits 15 to 20
is operated to 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 TO indicates that the circuit according to this example is in operation.
O is output from the heat controller 8, and is outputted to, for example, a host device via the output buffer 27.

[Output storage of recording data] When outputting recording data, the output data latch sections 28 to 33 store information on unused nozzles based on the output data of the output control devices 15 to 20. This data is held until cleared by output data latch controller 34.

Information on unused nozzles stored in the output data latch units 28 to 33 is set as cs=o, 'n=0, R53=1
At this time, 6 bytes of unused nozzle information is selected using the 3 bits R5O~2, and the output data control device 34 selects the unused nozzle information.
It is output as necessary and output to data buses DO 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 perform preliminary ejection from only the unused nozzles during one line. After this, C5 = O, RD
= O, by the signal of R53 to R50 = 1, the control device 3
4 outputs a signal for resetting the information of unused nozzles stored in the latch sections 28-33.

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, and in this example, it is also used as the main control section of an inkjet printer. Here, 300 is an Ml in the form of a microprocessor, for example, which controls each part according to the processing procedure shown in FIG.
ll, 303 is an interface unit that controls transmission and reception of image data and control signals related to recording with an external host device H.

A buffer memory section 307 temporarily stores image data transferred from the host device H.

306 is the cap 103 in FIG. cap motor 10
6 and a cap system 20 consisting of a cap sensor 110
The MPU 300 drives and controls the cap motor 106 via the cap system drive unit 306 based on the position information detected by the sensor 110, thereby driving the recording head 102 of the cap 103.
to open and close. 301 is the platen roller 10
1. Line feed motor 107 and paper sensor 109
A paper feeding system drive unit coupled to a paper feeding system 201 including a paper feeding system 201, etc.,
The MPU 300 controls the conveyance of the recording medium via the paper conveyance system drive section 301.

304 is a carriage on which the recording head 102 of FIG. 8 is mounted, and a carriage motor 108. This is a main scanning system drive unit that is combined with a main scanning system that includes the photosensor 104, etc.
300 controls scanning in the S direction in FIG. 8 via this drive unit 304. 302 is a control circuit shown in the first diagram for driving the recording head 102.

308 is a ROM that stores programs corresponding to processing procedures etc. which will be described later with reference to FIG. 5, and 309 is a RAM used for work. Moreover, 310 is the above-mentioned each part 300~
304. Address bus connecting 307 to 309.

This is a path line that collects a control bus and a data bus (Do NO3).

FIG. 5 shows an example of a preliminary ejection processing procedure by the control system shown in FIG. First, when recording is performed at one position in the main scanning direction (g direction) while driving the main scanning system 204 in step SL, it is determined in step s3 whether one main scanning is completed or not. If the determination is negative, the process returns to step S1 to continue recording. On the other hand, if the determination is affirmative, step S5
Then, the recording head 102 is moved to the home position to face the cap 103. At this time, paper feed system 2
01 may be driven to perform line feed.

In step S7, the cap system 306 is driven to join the cap 103 to the recording head 102, and in step S9, the above-mentioned status is sent to the control circuit 302 shown in the first diagram.
information about unused nozzles in the main scan is read out. In step Sll, based on the information, only the ejection energy generating elements corresponding to the nozzles not used in the main scanning are driven to perform preliminary ejection.

When this preliminary ejection is completed, the process proceeds to step 513, and the cap 103 is opened in preparation for the next scan.

Further, in step 515, the status is sent to the control circuit 302 to clear the data stored in the output data latch units 28-33.

According to this embodiment, preliminary ejection is performed only from unused nozzles to perform the ejection recovery process, so that the amount of ink consumed in the process can be reduced. Furthermore, if a control element such as an MPU manages the nozzles that are used or not used in the recording head, the recording speed is limited by the processing speed of the control element such as the MPU. By storing the memorization of used/unused nozzles in the recording control circuit, it was also possible to reduce the burden on control elements such as the MPU. This also makes it possible to reduce the cost of an inkjet printer using the control circuit according to this example, since there is no need to use expensive control elements such as high-speed MPUs even if the recording speed increases. Note that the preliminary ejection timing is 1 as described above.
Of course, it can be determined not only at the end of the main scan, but also at any desired time. For example, it may be performed every time a plurality of scans are performed, or it may be performed at the end of recording one page.

(Embodiment 2) FIG. 6 shows another embodiment of the present invention, in which corresponding parts are given the same reference numerals and explanations thereof will be omitted for each part that can be configured in the same manner as in FIG. 1. In the figure, 80 is a heat controller that controls the timing etc. when outputting recording data, and 65-70 are outputting recording data stored in recording data latch sections 9-14 under the control of heat controller 80. This is an output control circuit that drives only the nozzles that did not perform printing output during the ejection recovery process.

FIG. 7 shows a specific configuration example of the output control circuits 15 to 20 shown in FIG. In this example, 8 D-type flip-flops and 3
It consists of a state buffer, etc., and stores information about unused nozzles using a D-type flip-flop.

Further, a portion 80^ within the broken line in FIG. 7 is a circuit for resetting the flip-flop, etc., and this circuit can be provided in the heat controller 80.

Next, the operation of (Embodiment 1) will be explained step by step.

[When the power is turned on] When the reset signal ■ is input from the main control unit when the power is turned on, this signal is sent to the command register 5. The recorded data is transmitted to the latch controller 7 and the heat controller 8. At this time, the command data stored in the command register 5 is cleared, and the recording data latch controller 7 also clears the recording data stored in the print data latch units 9 to 14.

The heat controller 8 also includes output control circuits 15 to 20.
It resets the memory latches of unused nozzles built into the unit, and prohibits and stops recording data output.

This completes the operation when the power is turned on.

[When setting command] Control when setting command data is by signals R5O and R5I.

Command data is transmitted via data buses DO to D7.

In this example, the command setting operation is R5O=1, R5
I=1. This is performed by controlling the command register 5 via the line controller, the manual buffer 2, and the status controller 4 when n=o and c\=0. That is,
The host device inputs setting data such as the heat pulse width at the time of output, inversion/non-inversion of LSB to MSB in bit units of recording data, inversion/non-inversion of LSB to MSB in byte units of recording data, heat order, etc. It is output to buses DO to D7 and set in the command register 5 via the manual buffer 1.

[Recording data setting] Control when setting recording data is performed using signals R5O, R5I, and WR.
.

3, and the recorded data is transmitted via buses DO to D7.

In this example, the recording data setting operation is R5O=O, R5I
=o, n=o, and cs=o, and is performed by controlling the recording data latch controller 7 via the input buffer 2 and status controller 4. Bitwise LSB stored in command register 5
- Recording data supplied from the host device via DO to D7 is transmitted via the manual buffer 1 and the bit inverter 6 according to setting data for inverting/non-inverting the MSB and inverting/non-inverting each byte. Record data latch controller 7
The recorded data is stored in the designated recording data latch section of the recording data latch sections 9 to 14 under the control of.

[Output of Recorded Data] There are two ways to output the recorded data latched as described above. One is to start output operation by signal TOI, and the others are by signals R5O, R5I, T
f'U, (:S starts the output operation.

When either of these two output start signals is input manually, the heat controller 8 is activated and the output control circuits 15 to 20
is operated to 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 TO indicates that the circuit according to this example is in operation.
O is output from the heat controller 8, and is outputted to, for example, the host device via the output buffer 27.

[Output storage of recording data] When outputting recording data, information on unused nozzles is stored in flip-flop groups provided in each of the output control devices 15 to 20. This record data latch is held until cleared by the heat controller 80.

[Output to unused nozzles] When outputting to unused nozzles, Mf't1 etc. output the SEL signal shown in FIG. 7 to "H" via the heat controller 80.
” and send an output operation start signal (signal for operating all nozzles) with an appropriate heat pulse to the control circuit shown in Figure 6 according to this example in the same way as during normal recording, the circuit shown in Figure 7 will be created. This allows output to be performed only to unused nozzles.

Such preliminary ejection can be performed using the control system shown in FIG. 4 or the same processing procedure as shown in FIG. for example,
When preliminary ejection is performed on unused nozzles during one page, the following procedure may be used.

That is, the MPU 300 changes step S3 in FIG. 5 so that the carriage carrying the print head 102 moves to the home position at the end of the print operation for one page, and immediately sets the SEL signal to "H" after passing through step S7. Then, an output operation start signal is sent to the circuit according to this example using an appropriate heat pulse, and preliminary ejection is performed. When the preliminary ejection is completed, the SEL signal is set to "L" after step S13.
”, set the normal recording mode, and clear the latches of the unused nozzles (the D-type flip-flop group shown in FIG. 7).

This example also provides the same effects as (Example 1). In addition, the MPU 300 performs operations such as preliminary ejection after confirming information on unused nozzles once (Example 1)
Compared to , we have made it possible to simply separate the output into two motes, the normal recording output and the unused nozzle output during ejection recovery processing, and send the recording output operation start signal, so that the unused nozzle information can be retrieved. The procedure can be omitted, and the burden on the MPU 300 can be further reduced.

In addition, in the above two examples, the recording head is attached to the carriage +=
The present invention has been applied to a serial type inkjet printer that performs recording by main scanning in the main scan mode. It goes without saying that it is extremely effective and easily applicable to inkjet printers.

[Effects of the Invention] As explained above, according to the present invention, it has become easy to eject only unused nozzles within a certain period of time. That is, for example, if the present invention is applied to the control circuit of the recording head of a serial printer, it becomes possible to perform preliminary ejection only from the nozzles at the upper and lower ends of the recording head, which are rarely used in serial printers, and the ink can be ejected without wasting ink. It is possible to prevent defects. According to the applicant's measurements, it has been confirmed that the amount of ink consumed during preliminary ejection is less than the number specified above. This shows that the on-demand print head has the effect of significantly reducing the amount of wasted ink.

In addition, since the lifespan of a BJ head is largely dependent on wear and tear, the present invention, which performs preliminary ejection only from unused nozzles, instead of performing preliminary ejection uniformly as in the past, allows for variations in the frequency of use for each nozzle. The effect of suppressing the noise and increasing the lifespan of the BJ head was also achieved.

Furthermore, compared to methods that process unused nozzles using MPtl, etc., there is no need to increase processing such as managing used/unused data according to recorded data for ejection recovery processing, so MPII etc. This also has the effect of reducing the burden on users and enabling high-speed recording.

In addition, the present invention is easy to form into a gate array,
It is small and can be provided at low cost.

[Brief explanation of the drawing]

1 is a block diagram showing a first embodiment of the present invention, FIG. 2 is a circuit diagram showing an example of the configuration of the output data latch section in FIG. 1, and FIG. 3 is an output data latch control in FIG. 1. FIG. 4 is a block diagram showing a configuration example of a preliminary ejection control system using the circuit shown in FIG. 1; FIG. 5 is a discharge recovery process using the control system shown in FIG. 4. Flowchart showing an example of the procedure; FIG. 6 is a block diagram showing the second embodiment of the present invention; FIG. 7 is a circuit diagram showing an example of the configuration of the output data latch section in FIG. 6; FIG. 2 is a plan view showing an example of an inkjet blink to which the invention can be applied. 1-3...Manual buffer, 4...Status controller, 5...Command register, 6...Bit inverter, 7...Record data latch controller, 8...Heat controller, 9-14 ...Record data latch section, 15-20.65-70...Output control circuit, 21-2
7.35-... Output buffer, 28-33... Output data latch section, 34... Output data latch control device,
102... Recording head, 206... Cap system, 300... MPLI. Figure 3 Figure 5 Figure 8

Claims (1)

[Scope of Claims] 1) In a control circuit for an on-demand recording head having a plurality of nozzles for ejecting ink, a control circuit is provided corresponding to each of the plurality of nozzles, and a control circuit is provided in accordance with the driving of the recording head. 1. A control circuit for a recording head, comprising a latch means for latching information indicating that the nozzle is not in use. 2) A control circuit for a printhead according to claim 1, further comprising output means for making the information latched by the latch means readable. 3) In the recording head control circuit according to claim 1, in the process of ejecting ink to stabilize the ejection state of the plurality of nozzles, the latch 1. A control circuit for a recording head, comprising means for driving only the unused nozzles based on information obtained from the recording head.