JP3441905B2 - Recording apparatus and control method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus which drives a plurality of recording elements to form a visible image and a control method thereof.

[0002]

2. Description of the Related Art In a so-called inkjet printer which forms an image by ejecting a recording liquid (ink) as droplets from an orifice and adhering it to a recording medium (recording paper), in recent years, high quality and high speed have been remarkable. . As a method of increasing the speed of an inkjet printer, there is a method of increasing the number of nozzles as one of the methods that have been generally performed conventionally. By increasing the number of nozzles, the print width for printing one line (the print width of one print scan) has been increased to achieve high speed.

However, when the number of nozzles increases, an excessive voltage drop occurs when all the nozzles are driven at the same time, and if they are driven as they are, printing defects due to insufficient voltage will occur. For this reason, a method called block driving is used in which all nozzles are divided into some blocks and the driving timing is shifted for each block to reduce the number of elements driven at the same time and reduce the voltage drop.

[0004]

When the number of divided blocks is increased to reduce the amount of voltage drop, the voltage drop is certainly reduced. However, the increase in the number of blocks is
This leads to an increase in the time required to drive all the blocks, the drive frequency becomes slower, and the overall throughput drops. Therefore, the number of blocks to be divided cannot be increased in order to increase the speed.

On the other hand, in order to achieve high speed, it is sufficient to increase the number of nozzles. However, since the number of blocks to be divided cannot be increased for the above reason, the number of nozzles driven simultaneously (the number of nozzles in one block). However, there is a problem in that the voltage drop cannot be reduced even if the block drive is performed.

Conventionally, in such block driving, all nozzles are driven with a driving pulse width determined by the characteristics of the heater. Therefore, when driving all the nozzles in the same block at the same time or when only one nozzle is driven, they are driven with the same pulse width. It is clear that when all the nozzles in the same block are driven, the voltage drop becomes larger by the number of the nozzles than when only one nozzle is driven. For this reason, it is necessary to set the drive pulse to a longer pulse width in consideration of this voltage drop in case of driving all the nozzles in the block. That is, 1
Even if all nozzles in the block are driven at the same time, it is possible to provide sufficient power, and printing defects such as blurring caused by insufficient amount of ink being discharged from the heating element due to insufficient power due to insufficient voltage. Need to be prevented. However, if only one nozzle in one block is driven under this setting,
Since a large amount of electric power is applied to the heater of the nozzle, the life of the heater is shortened, and in the worst case, the heater is broken.

The present invention has been made in view of the above problems, and makes it possible to control the drive power in accordance with the number of recording elements that are simultaneously driven, and to perform stable recording operation regardless of the number of recording elements. It is an object of the present invention to provide a recording head, a recording apparatus, and a control method thereof that realize the above.

[0008]

A recording apparatus according to the present invention for achieving the above object has the following configuration. That is, a recording apparatus that performs recording using a recording head having a plurality of recording elements that can be driven simultaneously, and a plurality of blocks corresponding to the recording elements that are driven in block divisions.
A shift register for receiving the serial data <br/> take the data are arranged in serial, prior to be another count from among the serial data transferred to said shift register
A data separation circuit that separates the the data for each serial block,
A plurality of counters that separately count the number of recording elements to be driven for each data separated by the separation circuit , and a recording that is provided corresponding to the plurality of counters and determines a drive signal based on each count result. And means.

[0011] Preferably, the data separation circuit, the serial data, the data corresponding to the even-numbered recording elements, a circuit for separating the data corresponding to the odd-numbered printing elements, said plurality of counters Is separated
The data corresponding to the even-numbered recording element and the odd-numbered recording element
With a counter that counts separately from the data corresponding to the recording element
Yes, the plurality of counters are separated by even numbers.
Supports data corresponding to recording elements and odd-numbered recording elements
It is a counter that separately counts the data .

Further, preferably, the recording element has an electrothermal converter, and the recording means is means for determining a pulse width of an electric signal applied to the electrothermal converter.

[0011]

[0012]

[0013]

Also, preferably, the recording element is a heat
A recording head that uses energy to eject ink.
Heat to generate the thermal energy to be given to the ink.
Equipped with energy converter .

Further, a control method of a recording apparatus of the present invention which achieves the above object is a control method of a recording apparatus having a plurality of recording elements which can be simultaneously driven, wherein the recording elements driven by block division are a step of data <br/> data of a plurality blocks corresponding receives serial data arranged serially, said each of the blocks to be another count from the serial data data to be transferred to the shift register <br /> and the data separating step of separating the data, for each of said separated by a separation process data, each separate counter, a counting step for counting the number of recording elements to be driven, provided corresponding to the plurality of counters And a determining step of determining a drive signal based on each count result.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

[First Embodiment] <General Description of Apparatus Main Body> FIG. 1 is a schematic view of an ink jet recording apparatus to which the present invention can be applied. In the figure,
The lead screw 5005 rotates in conjunction with the forward / reverse rotation of the drive motor 5013 via the drive force transmission gears 5011 and 5009. The carriage HC has a pin (not shown) that engages with the spiral groove 5005 of the lead screw 5004, and is reciprocated in the directions of arrows a and b as the lead screw 5004 rotates. This carriage HC
Inkjet cartridge IJC is mounted on.

A paper pressing plate 5002 presses the paper against the platen 5000 in the moving direction of the carriage. Photosensors 5007 and 5008 are home position detecting means for confirming the presence of the carriage lever 5006 in this area and switching the rotation direction of the motor 5013. Reference numeral 5016 is a member that supports a cap member 5022 that caps the front surface of the recording head. Further, 5015 is a suction means for sucking the inside of the cap, and performs suction recovery of the recording head through the opening 5023 in the cap. 5017 is a cleaning blade.
Reference numeral 019 denotes a member that allows the blade to move in the front-rear direction, and these members are supported by the main body support plate 5018. Needless to say, a well-known cleaning blade can be applied to this example instead of this form. or,
Reference numeral 5021 denotes a lever for starting suction for suction recovery, which moves in accordance with the movement of the cam 5020 that engages with the carriage, and the driving force from the driving motor is movement-controlled by a known transmission means such as clutch switching. .

The capping, cleaning, and suction recovery are configured so that the desired processing can be performed at their corresponding positions by the action of the lead screw 5004 when the carriage comes to the area on the home position side. As long as the desired operation is performed at the timing, any of the above can be applied to this example.

<Description of Control Configuration> Next, a control configuration for executing the recording control of the above-mentioned apparatus will be described with reference to the block diagram shown in FIG. In the figure showing a control circuit, 1700 is an interface for inputting a recording signal, 1701 is an MPU, 1702 is a program ROM for storing a control program executed by the MPU 1701,
1703 is a dynamic type R for storing various data (recording data, recording data supplied to the head, etc.).
AM (hereinafter referred to as DRAM). A gate array 1704 controls the supply of print data to the print head 1708, and includes an interface 1700 and an MPU 170.
1. It also controls data transfer between the RAM 1703. 171
Reference numeral 0 is a carrier motor for carrying the recording head 1708, and 1709 is a carrying motor for carrying the recording paper.
Reference numeral 1705 denotes a head driver for driving the head, 170
Reference numerals 6 and 1707 denote motor drivers for driving the carry motor 1709 and the carrier motor 1710, respectively. In addition, 1711 is a control part, MPU1701,
ROM 1702, RAM 1703 and gate array 17
04.

The operation of the above control structure will be described. When a recording signal is input to the interface 1700, the gate array 1
A recording signal is converted between the 704 and the MPU 1701 to print data for printing. And the motor driver 1
The recording heads 706 and 1707 are driven, and the recording head is driven according to the recording data sent to the head driver 1705 to perform printing.

In the above structure, the head driver 17
Reference numeral 05 drives a plurality of nozzles of the recording head 1708 by dividing them into a plurality of blocks. The configurations and operations of the head driver 1705 and the recording head 1708 according to the first embodiment will be described below.

FIG. 3 is a block diagram showing a circuit constituted by the head driver 1705 and the recording head 1708 according to the first embodiment. In this embodiment, the total number of nozzles is 256, and this is divided into 16 blocks and driven. The nozzle pitch is 600 dpi.

1 is a block signal, which is 4 bits (BE
0 to BE4), and specifies the block number (0 to 15) of the block to be driven among the 16 blocks. Reference numeral 2 is a decoder, which sets the logic level of the signal line corresponding to the block number designated by the block signal 1 to H.
Turn to high. A heating element 3 is provided for each nozzle.

Reference numeral 6 denotes a shift register, which is pixel data 9 serially input through the gate array 1704.
Pixel clock signal 7 synchronized with the output of pixel data 9
Are sequentially stored in synchronism with and output as a 16-bit parallel signal. Reference numeral 5 is a latch, which latches 16-bit output data from the shift register 6 when the latch signal 4 is input. The latch signal 4 is a signal that is output every time one block of pixel data is stored in the shift register 6 (that is, every 16 pixel clocks).

Reference numeral 8 is a counter, which counts the number of pixels (in this example, the number of black pixels) for which ink is to be ejected from the input pixel data 9. The count value of the counter 8 is cleared by the latch signal 4, and counting is started from 1 again. Therefore, immediately before the count value is cleared by the latch signal 4, the counter 8 holds the count value corresponding to the number of black pixels in one block, that is, the number of nozzles to be simultaneously driven. Therefore, the latch 1 which holds the count value of the counter 8 by the latch signal 4
0 holds the number of black pixels in one block to be recorded next.

Reference numeral 12 is a pulse width control circuit, which outputs a heater driving pulse 13 when a heat signal 11 is input.
Here, the pulse width of the heater driving pulse 13 is the latch 1
Control is performed based on the counter value held at 0, that is, the number of nozzles to be driven at the same time. FIG. 4 is a diagram showing the relationship between the counter value held in the latch 10 and the pulse width of the heater driving pulse. As shown in the figure, the pulse width control circuit 12 increases the pulse width of the heater drive pulse to be output as the counter value increases, that is, as the number of nozzles driven simultaneously increases.

The block signal 1, the latch signal 4, the pixel clock signal 7, the pixel data 9, and the heat signal 11 are signals input from the control unit 1711 to the head driver 1705. Further, the AND circuit 14 is provided for each of the 256 heating elements 3, and enables the block driving of the heating elements 3 by taking the logical product of the heater drive signal and the block selection signal. Further, the AND circuit 15 includes the latch 5
The heater drive signal to be supplied to the AND circuit 14 is generated by taking the logical product of each of the pixel data of one block that is held and output by the heater drive pulse 13.

According to the above configuration, the decoder 2, the latch 5, and the AND circuits 14 and 15 realize the block drive in which the 256 heating elements 3 are divided into 16 times. Here, one block (1
When the data of 6 pixels) is held, the number of black pixels (the number of nozzles to be driven) in the block is held in the latch 10. Then, the pulse width control circuit 12 causes the heater drive pulse 1 having a pulse width corresponding to the numerical value held in the latch 10.
3 is output and provided to the AND circuit 15.

As a result, the pulse width of the heater driving pulse 13 becomes a pulse width corresponding to the number of nozzles driven by the pixel data held in the latch 5, and the heating element 3 can be driven appropriately. The pulse width control circuit 12 has a characteristic as shown in FIG. 4 and internally has a table for converting the count value to the pulse width, and outputs the pulse width determined by the input counter value. Thus, every time the heat signal 11 is input, the heater drive pulse signal 13 having a pulse width suitable for the number of recording pixels of the pixel data held in the latch 5 is supplied to the pulse width control circuit 1.
2 and the heating element 3 is appropriately driven. still,
The pulse width control circuit 12 controls the pulse width with the characteristic as shown in FIG. 5. For the control, for example, a clock signal faster than the pixel clock is set to a numerical value (pulse width) set according to the number of nozzles. (Corresponding to the above), and the drive pulse is output until the count up.

FIG. 5 is a diagram showing generation timings of the pixel clock signal 7, the latch signal 4, the block signal 1, the heat signal 11 and the heater driving pulse 13 in the first embodiment. As is clear from the above description and FIG.
The latch signal is input once every 16 pixel clocks. The block signal 1 is set in synchronization with the latch signal 4 to select the block, and the heater drive pulse 13 is generated and output based on the heat signal 11 and the number of black pixels in the block. . That is, the pulse widths t1 and t2 of the heater driving pulse 13 are determined as shown in FIG. 4 based on the number of black pixels in the corresponding block.

The problems in the conventional heater driving are summarized as follows. That is, when the number of the heating elements 3 to be driven at one time is 16, a current value 16 times as large as that in the case of only one heating element 3 flows, and the voltage drop becomes 16 times. Therefore, if the 16 heating elements 3 are driven with the pulse width when discharging only one heating element 3 without considering the voltage drop as it is, the voltage becomes insufficient,
Ink cannot be ejected from the 16 nozzles, and the print result is faint. On the other hand, if the width of the drive pulse for driving the heating element 3 is set to be longer in consideration of the voltage drop when driving 16 heating elements, 16 heating elements will be driven. The heating element is driven with a pulse width capable of driving. For this reason,
Excessive heat stress is applied to the heating element, and the life of the heating element is significantly impaired.

On the other hand, according to the above embodiment, the drive pulse width is appropriately set by the pulse width control circuit 12 according to the number of nozzles to be driven. For example, 1
1 more than the pulse width when driving all 6 heating elements
The pulse width at the time of driving the heating element of the book is set shorter and driven (see FIG. 4). As described above, in the present embodiment, the number of driving lines is detected by counting the data of the black pixels in the shift register 6, and the pulse width is controlled each time according to the number of driving lines. Therefore, it is possible to prevent excessive heat stress from being applied to the heating element, and prevent a situation in which the life of the heating element is shortened.

[Second Embodiment] Next, a second embodiment will be described. FIG. 6 is a block diagram showing the configurations of the head driver and the print head of the printing apparatus according to the second embodiment. The external appearance and schematic control configuration of the recording apparatus according to the second embodiment are the same as those of the first embodiment (FIGS. 1 and 2).

In the second embodiment, the total number of nozzles is 64. The shift register 106 has 64 bits for the total number of nozzles. Pixel data 109 is serially input to the shift register 106 in synchronization with the pixel clock 107,
When the pixel data for 64 pixels is complete, the latch 105
Latched by. The latch timing is determined by the latch signal 104. In the second embodiment, the number of time-division driving is 2, and the nozzle 32 of odd SEG is 32.
And 32 even-numbered SEG nozzles, which are simultaneously ejected.

The pixel data 109 is the data separation circuit 123.
SEG1, SEG3, ... SEG63 odd SE
G and even numbers of SEG2, SEG4, ... SEG64
It is separated into two. Then, among the separated 32 bits, the number of the heating elements 103 that are actually driven is counted by the counters 108a and 108b. The counter 108a is for even-numbered SEG, and the counter 108a
b is for odd SEG.

Pulse width control circuit 112a for even SEG
And the pulse width control circuit 112b for odd SEG has 32
It is a circuit that outputs a heater driving pulse 113 having a pulse width as shown in FIG. 7 with respect to a step input value.

The latch signal 104 and the heat signal 111 are synchronized, and the heat signal 111 is the pulse width control circuit 11.
When 2a and 2b are entered, the 64-bit data latched by the latches 110a and 110b change the output value corresponding to the count value in each pulse width control circuit 112 to an odd SE.
G and even SEG are applied to drive each heating element 103. In this way, the width of the heater driving pulse is controlled by the pulse width control circuits 112a and 112b according to the number of driving lines. By doing so, as shown in the first embodiment, it is possible to prevent an excessive thermal stress from being applied to the heater, and it is also possible to prevent the occurrence of blurring when driving a large number of nozzles.

As described above, according to each of the above-described embodiments, a counter circuit is added to the data serially sent to the shift register to count the number of driven heating elements. It is possible to suppress the cost increase due to. Further, since the heating element does not receive more energy than necessary, the life of the heater is extended.

Even when the present invention is applied to a system composed of a plurality of devices (for example, host computer, interface device, reader, printer, etc.), a device composed of one device (for example, copying machine, facsimile) Device).

In the above embodiment, the pulse width control based on the number of driving nozzles is performed by hardware such as a counter and a latch circuit. However, it goes without saying that part or all of the pulse width control described in the above embodiment may be realized by software. In this case, a storage medium storing a program code of software that realizes the functions of the above-described embodiments is supplied to a system or apparatus, and the computer (or CPU or MPU) of the system or apparatus stores the program in the storage medium. The functions of the above embodiments are achieved by reading and executing the code.

In this case, the program code itself read from the storage medium realizes the function of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

A storage medium for supplying the program code is, for example, a floppy disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD.
-R, magnetic tape, non-volatile memory card, ROM, etc. can be used.

Further, by executing the program code read by the computer, not only the functions of the above-described embodiment are realized, but also the OS (operating system) running on the computer based on the instruction of the program code. It is needless to say that this also includes a case where the above) performs a part or all of the actual processing and the processing realizes the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written in the memory provided in the function expansion board inserted into the computer or the function expansion unit connected to the computer, based on the instruction of the program code, It goes without saying that a case where the CPU or the like included in the function expansion board or the function expansion unit performs some or all of the actual processing and the processing realizes the functions of the above-described embodiments is also included.

[0046]

As described above, according to the above embodiment, the driving power can be controlled according to the number of recording elements that are driven at the same time, and stable recording operation can be performed regardless of the number of recording elements. Can be realized.

[0047]

[Brief description of drawings]

FIG. 1 is a schematic view of an inkjet recording apparatus to which the present invention can be applied.

FIG. 2 is a block diagram showing a schematic control configuration in the inkjet recording apparatus of FIG.

FIG. 3 is a block diagram showing a circuit configured by a head driver and a recording head according to the first embodiment.

FIG. 4 is a diagram showing a pulse width control circuit according to the first embodiment,
It is a figure which shows the relationship between the counter value and the pulse width of a heater drive pulse.

FIG. 5 is a diagram showing generation timings of a pixel clock signal, a latch signal, a block signal, a heat signal, and a heater driving pulse in the first embodiment.

FIG. 6 is a block diagram showing a detailed configuration of a head driver and a recording head of the recording apparatus according to the second embodiment.

FIG. 7 is a diagram illustrating a pulse width control circuit according to a second embodiment,
It is a figure which shows the relationship between the counter value and the pulse width of a heater drive pulse.

[Explanation of symbols]

1 block signal 2 decoder 3, 103 heating element 4, 104 Latch signal 5, 10, 105, 110a, 110b Latch 6,106 shift register 7,107 pixel clock signal 8,108a, 108b counter 9,109 pixel data 11,111 Heat signal 12, 112a, 112b Pulse width control circuit 13,113 Heater drive pulse

Continuation of the front page (56) Reference JP-A-5-50642 (JP, A) JP-A-7-125261 (JP, A) JP-A-60-59858 (JP, A) JP-A-60-23063 (JP , A) JP-A-3-79377 (JP, A) JP-A-2-508 (JP, A) JP-A-2-289353 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB) Name) B41J 2/01 B41J 2/045-2/055 B41J 2/355

Claims (7)

(57) [Claims] 1. A recording apparatus that performs recording using a recording head having a plurality of recording elements that can be driven simultaneously, and a plurality of blocks corresponding to the recording elements that are driven in block divisions.
Serial data with lock data arranged serially
A shift register for receiving the data, the data separating circuit for <br/> separated into data of the respective blocks to be another count from among the serial data transferred to said shift register, separated by the separation circuit A plurality of counters that separately count the number of recording elements to be driven for each data , and a recording unit that is provided corresponding to the plurality of counters and that determines a drive signal based on the respective count results are provided. Recording device. Wherein said data separator circuit comprises a serial data, and data corresponding to the even-numbered recording elements, circuits der to separate the data corresponding to the odd-numbered recording elements
And the plurality of counters are separated by even-numbered records.
Corresponding to the data corresponding to the element and the odd number recording element
The recording apparatus according to claim 1, wherein the recording apparatus is a counter that separately counts data . 3. The recording according to claim 1, wherein the recording element has an electrothermal converter, and the recording means is means for determining a pulse width of an electric signal applied to the electrothermal converter. apparatus. 4. The recording element is a recording head for ejecting ink by utilizing thermal energy, and is provided with a thermal energy converter for generating thermal energy applied to the ink. Item 2. The recording device according to item 1. 5. A method of controlling a printing apparatus having a plurality of printing elements that can be driven simultaneously, wherein a plurality of blocks corresponding to the printing elements that are driven in block divisions are used.
Serial data with lock data arranged serially
A step of receiving the data, a data separating step for dividing <br/> away to the data for each of the blocks to be another count from among the serial data transferred to the shift register, the data separated by the separation step for each, in each separate counter, a counting step for counting the number of recording elements to be driven, by a drive means provided corresponding to the plurality of counters, determination step of determining a driving signal based on the respective count results A method for controlling a recording apparatus, comprising: 6. In the separating step, the serial data is separated into data corresponding to even-numbered recording elements and data corresponding to odd-numbered recording elements, and the count is performed.
The process corresponds to the data corresponding to the even-numbered recording elements separated.
Data separately from the data corresponding to the odd-numbered recording elements.
Control method for a recording apparatus according to claim 5, the count to Rukoto characterized in motor. 7. The control of a recording apparatus according to claim 5, wherein the recording element has an electrothermal converter, and the determining step determines a pulse width of an electric signal applied to the electrothermal converter. Method.