JP2752492B2 - Recording device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus having a thermal head, which is applicable to a so-called thermal printer, an ink jet printer, and the like.

[Prior Art] As is conventionally known, a thermal printer based on a thermal recording system or a thermal transfer recording system is widely used as a printer capable of obtaining a high-quality image with high reliability because non-impact recording is performed. . These printers use a thermal head. Similarly,
A thermal head provided with an electrothermal converter is also used in an ink jet printer of a bubble jet recording system for discharging ink using thermal energy to form ink droplets.

That is, in a thermal printer, a pulse corresponding to an image signal is applied to an electric resistor included in a thermal head to melt or soften a colored ink such as an ink ribbon, and this is applied to a recording material such as recording paper. To obtain a recorded image. Also, in an ink jet printer, a pulse is applied to an electric resistor disposed at a predetermined position in a liquid path in which ink is contained, and the liquid ink is heated and foamed by being discharged from the discharge port. As a result, a recorded image is obtained.

FIG. 12 shows an example of a drive circuit conventionally employed for controlling the pulse width applied to the above-described electric resistor. In this figure, R is an electric resistor, "STB" is AND
A terminal to input the strobe signal for pulse width control applied to the gate, "Latch" is a terminal to input a latch signal to temporarily store each bit data of the shift register SR, and "Data" is to each electric resistor. "Clock" is a terminal for inputting a data signal representing the corresponding dot information, and a terminal for inputting a clock signal for taking the data signal into the shift register SR.

[Problems to be Solved by the Invention] However, in the above-described conventional driving circuit, the AND gate is uniformly opened and closed in response to the application of the strobe signal STB. There is a disadvantage that it cannot be controlled to have different values.

More specifically, in order to obtain a high-quality image due to thermal conditions, it is effective to apply a pulse having a different width to each electric resistor in a recording method using a thermal head. However, the conventional circuit as shown in FIG. 12 cannot perform such individual control.

On the other hand, if the strobe signal input terminal STB is provided separately for each electric resistor, direct control from the outside is possible.However, the number of STB terminals is required by the number of electric resistors, and the connector And the required number of connections are unrealistic values.

In view of the above, an object of the present invention is to provide a recording apparatus configured to individually control heat generation of an electric resistor in order to obtain a high-quality image.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a recording head that drives a plurality of electric resistors provided in a recording head by a plurality of pulses corresponding to image signals. In a recording apparatus for forming an image on a material, a conduction time for at least one of the plurality of pulses which are sequentially transferred in synchronization with a clock during image formation and supplied to each of the electric resistors is designated. Storage means for temporarily storing the pulse width data corresponding to each of the image signals, and the plurality of pulses including a pulse having a width corresponding to each pulse width data stored in the storage means. Pulse output means for supplying each of the electric resistors.

Here, the storage means is pulse width data for specifying an energization time for each of the plurality of pulses, and stores sub-heat width data and main heat width data, and the pulse output means is stored in the storage means. The sub-heat pulse and the main heat pulse may be output at predetermined intervals in accordance with the sub-heat width data and the main heat width data. Further, the thermal head is capable of forming an image by ejecting ink droplets using thermal energy generated by an electric resistor, and landing the ink droplets on a recording material.

[Operation] In the present invention, pulse width data that is sequentially transferred in synchronization with a clock during image formation and specifies the energizing time for at least one of a plurality of pulses supplied to each of the electrical resistors is defined as: Since a plurality of pulses including a pulse having a width corresponding to each pulse width data are temporarily supplied to each of the electric resistors, each of the electric resistors is stored. The drive control is performed by giving an appropriate pulse waveform corresponding to the image signal, and each of the electric resistors is individually heated so that a high-quality recorded image can be obtained.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of a thermal head drive circuit included in a recording apparatus to which the present invention is applied. In this figure, 21 is 5
A shift register that shifts data for each bit in synchronization with a clock signal, 24 is an OR gate, 25 is a switching element, and 26 is an electric resistor.

 Next, the operation of this embodiment will be described.

First, 5-bit pulse width control data is input to each stage of the shift register 21 in synchronization with a clock signal. As a result, the quaternary counter 22 and the octal counter 23 store the LSB2 bits and the
The three MSB bits are input as the counter setup value (initial setting value). Then, when the first pulse counter clock is applied to the PC and the terminal, a pulse having a width corresponding to the setup value is output from the octal counter 23 to the OR gate 24, and the switching element 25 is turned on. As a result, a current having a pulse width corresponding to each setup value is supplied from the power supply _VH to the electric resistor 26.

Further, at the next timing subsequently, when the second pulse counter clock is applied to the PC ₂ terminal, likewise pulse-4 counter with a width corresponding to the setup value
The signal is output from 22 to the OR gate 24, and each electric resistor is driven.

As described above, the first pulse width and the second pulse width can be arbitrarily set (here, each of eight gradations and four gradations) using 5-bit data. Here, the interval between the first pulse and the second pulse can be controlled by the input timing of the first and second pulse counter clocks as shown in FIG.

The third figure, a Data is 101 setup value to be entered as specific examples in the octal counter 23, when Data setup values of the quaternary counter 22 is 00, PC ₁ terminal and PC ₂ terminal 3 shows a pulse waveform output in response to a pulse counter clock applied to the pulse counter.

That is, 101 of Data inputted to the octal counter 23 represents "5", and the output pulse 1 is obtained in a state where the remaining 3 bits are set to Hi for 8 bits. Data 00 input to the quaternary counter 22 is "0", and the output pulse 2 is obtained in a state where the remaining 4 bits are set to Hi for 4 bits.

As described above, by having the first pulse counter 23 and the second pulse counter 22, two independent pulse generations can be applied corresponding to the electric resistor. Two adjacent pulses can be obtained.

The reason why a high-quality image can be obtained by appropriately controlling these two adjacent pulses will be described below, taking an ink jet printer as an example. That is, the necessity of applying two adjacent pulses as shown in FIG. 4 in a bubble jet type ink jet printer that obtains a recorded image by discharging a colored liquid ink from a discharge port by thermal energy will be described.

Following the subheat pulse indicated by τ _S in FIG.
_When a main heat pulse indicated by τ _M is applied to the electric resistor after the _off time, τ _S and τ _M are appropriately selected and τ _{S
When off} is changed, as shown in FIG. 5, the amount of ejected ink changes, and the dot diameter to be printed changes. FIG. 5 shows characteristics when τ _S is changed to 2 μSec, 3 μSec, and 4 μSec. Therefore, τ _S , τ
it is possible to control the recording dot diameter by controlling the _off and tau _M, and to correct the unevenness of image, it is possible to halftone recording by dot size modulation.

That is, the present embodiment is provided with variable pulse width output means that can arbitrarily control each pulse width of τ _s , τ _off , and τ _M to a value such that a desired recording can be obtained. is there.

FIG. 6 shows a configuration example of a liquid jet recording apparatus (ink jet recording apparatus) to which the present invention is applied, and FIG. 7 shows a configuration example of the recording head.

First, in FIG. 6, reference numeral 14 denotes a head cartridge, which integrally includes a recording head formed using a heater board and an ink tank as an ink supply source. The head cartridge 14 is fixed on the carriage 15 by a pressing member 41, and these can reciprocate in the longitudinal direction along the shaft 21. The ink ejected from the recording head is separated from the recording head 18 by a very small distance from the recording head 18 with the recording surface regulated by the platen 19.
And an image is formed on the recording medium 18.

An ejection signal corresponding to image data is supplied to the recording head from a suitable data supply source via a cable 16 and a terminal connected thereto. One or a plurality of head cartridges can be provided according to the ink color used.

In FIG. 6, reference numeral 17 designates the carriage 15 as a shaft.
A carriage motor for scanning along 21 and a wire 22 for transmitting the driving force of the motor 17 to the carriage 15. Reference numeral 20 denotes a recording medium connected to a platen roller 19.
Is a feed motor for transporting the paper.

FIG. 7 shows a configuration example of a recording head according to this embodiment. Here, reference numeral 1 denotes a heater boat, which is formed by forming an electrothermal transducer (discharge heater) 5 and a wiring 6 made of Al or the like for supplying electric power to the silicon substrate by a film forming technique. And
A liquid jet recording head is formed by adhering a top plate 30 provided with a partition for limiting the liquid path (nozzle) 25 of the recording liquid to the heater board 1.

The recording liquid (ink) is supplied to the supply port 24
The liquid is supplied to the common liquid chamber 23, and is guided into each nozzle 25 from here. When the heater 5 generates heat by energization,
Bubbling occurs in the ink filled in the nozzle 29, and the discharge port 26
That is, more ink droplets are ejected.

FIG. 8 schematically shows a partial longitudinal sectional view of an ink ejection section of the recording head.

In FIG. 8, a surface of the recording head 39 facing the recording medium 31 has a plurality of ink ejection ports 40 at a predetermined pitch in the vertical direction.
Is formed. An electrothermal transducer 41 provided in an ink liquid passage communicating with each ink ejection port 40 is driven (electrically heated) based on dot information to generate a bubble 41A in the ink,
At this time, a flying ink droplet 42 is formed by the pressure fluctuation caused by the change of the bubble, and the recording is performed while the ink dots are attached to the recording medium 31 in a predetermined pattern.

Each recording head 39 is mounted with a circuit board of a driving circuit (driver) for performing the above-described driving.

Using the above recording head and its driving system,
For example, a line printer capable of full-color recording as shown in FIG. 9 can be constructed.

In Figure 9, 201A and 201B are rollers provided for holding and conveying the recording medium R in a sub-scanning direction V _S. 202BK, 202Y, 202M, and 202C are full multi-type recording heads that perform black, yellow, magenta, and cyan recording with nozzles arranged over the entire width of the recording medium R, respectively. It is arranged.

Reference numeral 200 denotes a recovery system, which faces the recording heads 202BK to 202C instead of the recording medium R in the ejection recovery processing. However, in this example, since the preliminary heating is performed at an appropriate timing, the number of times of starting the discharge recovery processing can be significantly reduced.

Next, it will be shown that the present invention is effective for a printer using a thermal transfer recording method.

FIG. 10 is a schematic view of a serial type thermal transfer printer. In the figure, an electric resistor array 71-C is arranged at the edge of the thermal head 71. Then, the thermal transfer ribbon (ink ribbon) 72 is softened by the heat generated by the electric resistor, and is transferred to the recording material 74 to form an image. In this case, by applying a pulse as shown in FIG. 4, the temperature distribution of the heated ink becomes flat, and the temperature can be controlled to an appropriate temperature according to the thermal characteristics of the ink.

Further, a method has been proposed in which light and heat are selectively applied to the ink riboin to change the transfer characteristics to form a transfer image, and then transferred to a recording material to obtain an image.
Since the heating temperature distribution of the ink ribbon can be made flat by applying the pulse waveform shown in the figure,
A highly accurate and stable transfer image can be formed.

As described above, in the recording method using a thermal head, a high-quality image can be obtained by applying a plurality of pulses, and a thermal head capable of applying a pulse of an arbitrary width to the electric resistor is essential for this purpose.

Further, in the above-described example, the case of two adjacent pulses has been described, but the same effect can be obtained by applying three or more pulses.

FIG. 11 shows a drive circuit according to another embodiment. This example uses the drive circuit shown in FIG.
_In contrast to the configuration in which the input is divided and input in advance as ₁ and CP ₂ , the signal input from the CCK terminal is
This shows a configuration in which control of outputs from CNTA and CNTB is controlled by signals input from SELII and SEL2 while applied to both of them. In this embodiment, 7-bit data is input to the shift register 81 in synchronization with the shift clock from the Sck terminal, and a latch pulse is applied to the LAT terminal to set data as a setup value of the counters A and B. Here, the counter A has 3 bits and the counter B has 4 bits.

When a counter clock is input to the CCK terminal while a high-level signal is input to the SELII terminal and a low-level signal is input to the SEL2 terminal, the counter CNTB is not driven and the counter is not driven.
Only the CNTA counts up, a pulse of a width corresponding to the setup data is output, and the drive switch element 85 is controlled to open and close via the OR gate 84 and the strobe gate 87, whereby the drive current is supplied to the electric resistor 86 Is done.

Next, while inputting a low level signal to the SELII terminal and a high level signal to the SEL2 terminal, input a clock to the CCK terminal, do not drive the counter CNTA, operate only the counter CNTB, and generate the second pulse. Apply.

As described above, the provision of the counters CNTA and CNTB functioning as two application pulse generation means enables two adjacent pulses to be applied to the electric resistor.

In the above-described embodiment, the counter circuit is used as the pulse generating means. However, a logic circuit such as a flip-flop or a one-shot multivibrator circuit may be used. The signal may be an applied pulse.

(Others) The present invention brings about an excellent effect particularly in a recording head and a recording apparatus of a bubble jet system among ink jet recording systems. This is because according to such a method, it is possible to achieve higher density and higher definition of recording.

As for the representative configuration and principle, it is preferable to use the basic principle disclosed in, for example, US Pat. Nos. 4,723,129 and 4,740,796. This method can be applied to both the so-called on-demand type and the continuous type. In particular, in the case of the on-demand type, it is arranged corresponding to the sheet or the liquid path holding the liquid (ink). Applying at least one drive signal corresponding to the recording information and providing a rapid temperature rise exceeding nucleate boiling to the electrothermal transducer, thereby causing the electrothermal transducer to generate thermal energy, thereby causing the recording head to emit heat energy. This is effective because a film in the liquid (ink) corresponding to the driving signal can be formed one by one by causing film boiling on the heat acting surface. The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble to form at least one droplet. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of a liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. U.S. Pat. No. 44
Those described in JP-A-63359 and JP-A-4345262 are suitable. Further, when the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As a configuration of the recording head, in addition to a combination configuration (a linear liquid flow path or a right-angled liquid flow path) of a discharge port, a liquid path, and an electrothermal converter as disclosed in the above-mentioned specifications, A configuration using U.S. Pat. No. 4,558,333 and U.S. Pat. No. 4,459,600, which disclose a configuration in which is disposed in a bending region, is also included in the present invention. In addition, Japanese Unexamined Patent Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, and an opening for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration is based on JP-A-59-138461, which discloses a configuration corresponding to a discharge unit. That is, recording can be performed reliably and efficiently regardless of the form of the recording head.

Further, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium on which a recording apparatus can record. Such a recording head may have a configuration that satisfies the length by a combination of a plurality of recording heads, or a configuration as one integrally formed recording head. In addition, a replaceable chip-type recording head that can be electrically connected to the device main body or supplied with ink from the device main body by being attached to the device main body even in the serial type as described above. The present invention is also effective when a cartridge type recording head provided integrally with the recording head itself is used.

Further, it is preferable to add recovery means for the print head, preliminary auxiliary means, and the like provided as a configuration of the printing apparatus in the present invention since the effects of the present invention can be further stabilized. If these are specifically mentioned, capping means for the recording head, cleaning means, pressurizing or suction means, preheating means using an electrothermal transducer or another heating element or a combination thereof, Performing a preliminary ejection mode in which ejection is performed separately from printing is also effective for performing stable printing.

Regarding the type or number of print heads to be mounted, for example, in addition to one provided for single color ink, a plurality of print heads are provided corresponding to a plurality of inks having different print colors and densities. May be used.

In addition, the form of the ink jet recording apparatus of the present invention may be used as an image output terminal of an information processing apparatus such as a computer, a copying apparatus combined with a reader or the like, or a facsimile apparatus having a transmission / reception function. It may be something.

[Effects of the Invention] As described above, according to the present invention, a pulse close to each of the electrical resistors can be applied with an appropriate waveform, and the recording dot diameter can be controlled. It is possible to provide a recording apparatus that can correct unevenness and perform halftone recording by dot diameter modulation, and can easily obtain high-quality images at high speed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a thermal head driving circuit according to an embodiment of the present invention, FIGS. 2 to 5 are diagrams for explaining the operation of the present embodiment, and FIGS. 6 to 9 are the present invention. FIG. 10 is a schematic diagram of a thermal transfer printer to which the present invention is applied, FIG. 11 is a diagram showing a thermal head driving circuit according to another embodiment of the present invention, and FIG. FIG. 9 is a circuit diagram for explaining a conventional technique.

Continuation of the front page (56) References JP-A-62-179946 (JP, A) JP-A-63-71373 (JP, A) JP-A-3-15556 (JP, A) JP-A-63-1559 (JP) , A)

Claims (3)

(57) [Claims] In a recording apparatus for forming an image on a recording material by driving a plurality of electric resistors provided on a recording head by a plurality of pulses corresponding to an image signal, a clock signal is output during the image formation. Pulse width data that is sequentially transferred in synchronization and specifies the energization time for at least one of the plurality of pulses supplied to each of the electrical resistors is temporarily stored in correspondence with each of the image signals. And pulse output means for supplying the plurality of pulses including a pulse having a width corresponding to each pulse width data stored in the storage means to each of the electric resistors. Characteristic recording device. 2. The storage means stores sub-heat width data and main heat width data as pulse width data for specifying an energization time for each of the plurality of pulses. The pulse output means stores the pulse width data in the storage means. 2. The recording apparatus according to claim 1, wherein the sub-heat pulse and the main heat pulse are output at predetermined intervals in accordance with the stored sub-heat width data and main heat width data. 3. The image forming apparatus according to claim 2, wherein the thermal head uses thermal energy generated by an electric resistor to eject ink droplets and land ink droplets on a recording material to form an image. The recording device according to claim 1.