JPH04142937A - Recording device - Google Patents

Abstract

PURPOSE:To obtain a recording device capable of moderating density variations generated before or after the interruption of an increase in the temperature of a recording element by providing a head drive control device which connects a drive signal to a recording head in accordance with temperatures stored in a temperature storage device and an interruption time counted by a standby time counting device at the time of resumption of a recording action after interruption. CONSTITUTION:If it is interpreted that the recording of drive data incorporated in memory in an interface 103 has ended, a recording head 12 is moved to a standby position such as a home position. At the same time, a standby time begins to be counted. With this process, the temperature of the recording head is detected when the scan of a specified amount using the head is terminated, and the head enters a standby state after the temperature is stored in RAM 111A. In addition, if it is interpreted that the standby state prevails after the recording is interrupted, the standby time counted so far is detected and with this procedure, a counting time is reset. After that, the recording head 112 is moved to an ink receptacle 160 and the ink is only discharged without actual printing work. This discharge is performed for determining the number of discharges for non-actual printing purposes referring to a table stored in ROM 111B and based on recording head temperatures before standby and detected standby time. If this discharge action ends, the recording head starts a recording action.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a recording apparatus, and more particularly to a recording apparatus having a standby mode for interrupting recording during recording.

[Conventional technology]

As this type of recording device, digital recording devices such as an inkjet recording method and a thermal transfer recording method are conventionally well known.

Particularly, inkjet recording devices have advantages such as easy color printing, and are popular as, for example, computer graphics output devices.

FIG. 7 is a block diagram showing a configuration when an inkjet recording device is used as an output device for computer graphics. In FIG. 7, the image data held by the host computer 101 is
03 and is temporarily stored in a memory (not shown) within the interface 103. The interface 103 converts the image data in the memory into a format that can be processed by the inkjet printer, and then transfers the data to the inkjet printer 105. The inkjet printer 105 performs printing according to the transferred image data.

In the above configuration, the memory capacity of the interface is generally several megabytes to several tens of megabytes, but the amount of image data held by the post computer may sometimes exceed this. In such a case, the postcomputer may transfer data as much as the memory capacity of the interface, and after the recording of these data is completed, it may further transfer the remaining data and perform recording based on this data. can. At this time, after the printer performs printing based on the data from the interface, it interrupts the conveyance of the printing paper and the driving of the printing head, and waits for the next data to be transferred. As a result, the system for image recording having the above-mentioned configuration can:
It becomes possible to handle an amount of image data larger than the memory capacity of the interface and perform recording based on this data.

However, in the case of a recording apparatus having a standby mode in which the recording operation is interrupted, there are the following problems.

That is, the density of the recorded image may change discontinuously before and after the standby.

This is not preferable from the standpoint of recording stability, and particularly if the above-described density change occurs on the same recording paper, the image quality will be significantly impaired.

FIG. 8 is a schematic diagram of the recording paper when the above-mentioned standby state occurs while recording is performed on one recording paper. In Figure 8,
It is assumed that the recording width of the recording head, that is, the length of the range in which ejection ports are arranged in an inkjet recording head, is d, and image recording is performed by scanning in the X direction in the figure. Also,
A total of 24 scans of images can be recorded on one sheet of recording paper shown in the figure, but the memory capacity of the interface is only 5.
Assume that there is only enough capacity for scanning.

In such a case, first, the portion indicated by A in the figure is continuously recorded, and then a standby state is entered until the image data of the portion indicated by B is transferred. After this transfer is completed, recording is performed continuously on part B, and then the apparatus enters a standby state again until the image data of part C is transferred. After this transfer is completed, recording is performed continuously on portion C, and recording for one sheet of recording paper is completed.

By the way, the temperature of a recording head generally rises when recording is performed continuously. For example, in an inkjet recording head, an ejection energy generating element for ejecting ink generates thermal energy as the ink is ejected, raising the temperature of the head.

Even in a thermal transfer type recording head, the temperature of the head increases due to heat generated by a heating element. When the temperature rises in this way, for example, in an inkjet recording head, the viscosity of the ink decreases, the amount of ink discharge increases, and the recording density increases. Furthermore, in the thermal transfer method, the amount or area of transferred ink increases, and the density similarly increases. However, once the printer enters a standby state for recording, the temperature drops, and the recorded density may drop in the recording immediately thereafter. This phenomenon occurs to some extent with any type of recording head, but it is especially true of so-called bubble jet recording heads, which use a heater to generate heat to boil ink and eject it using the pressure of the resulting bubbles. Remarkable.

FIG. 9 shows changes in recording density when performing image recording as shown in FIG. 8.

As shown in Figure 9, during continuous recording, the temperature of the recording head increases little by little and the density increases accordingly, so the change in density is not noticeable, but as shown in the figure. When the recording standby state shown by E enters the recording standby state, a rapid change in density occurs as the temperature of the recording head decreases. A problem arises in that the difference in density between the areas where the image is applied becomes very noticeable.

On the other hand, conventionally, in order to keep the head temperature constant before and after such a standby state, for example, the recording head is equipped with a temperature detecting means such as a thermistor and a heat-retaining heater.
It is well known to control the temperature by driving a heat-retaining heater in accordance with the head temperature detected by a temperature detection means.

[Problem to be solved by the invention]

However, this type of temperature control has a slow response when the temperature is rapidly changing. It was difficult.

In particular, when one printhead is equipped with one thermistor and a heater and the entire printhead is to be controlled at a constant temperature, even if the temperature detected by the thermistor has reached a predetermined temperature, the ejection energy generating element is The temperature of the ink in the liquid path, which is the place where ejection energy is applied to the ink, has not yet reached that temperature, and if printing is performed in this state, a difference in density will often remain. For this reason, the ink in the liquid path that is directly involved in ejection is removed as quickly as possible (
Raising the temperature to a certain level is required to overcome this phenomenon.

The present invention has been made in view of the above-mentioned problems, and its purpose is to resume recording after interrupting recording in a recording apparatus that has a mode in which recording is interrupted during image recording and enters a standby state. Before printing, the print element of the print head is driven in advance according to the print head temperature immediately before printing is interrupted, the time of printing interruption, etc., and the temperature of the print element is increased to increase the density that occurs before and after the interruption. The object of the present invention is to provide a recording device that can suppress the difference.

[Means to solve the problem]

To this end, in the present invention, in a printing apparatus having a standby mode in which a printing operation is interrupted during printing and stands by, a printing head for printing on a printing medium, a head temperature detection means for detecting the temperature of the printing head, storage means for storing temperature information detected by the head temperature detection means when recording is interrupted in the standby mode; standby time clock means for timing the interruption time of the recording operation; The present invention is characterized by comprising head drive control means for supplying a drive signal to the recording head in accordance with the temperature stored in the temperature storage means and the interruption time measured by the standby time measuring means.

[Function] According to the above configuration, a print head drive signal for temperature control at the time of restarting recording is determined according to the print head temperature at the time of recording interruption and the interruption time, and this signal causes the recording head to be activated in advance. For example, in the case of an inkjet recording head, the higher the temperature at the time of interruption or the longer the interruption time, the higher the number of ejection pulses or the wider the pulse width of the drive pulse. As a drive signal, it is possible to quickly restore the temperature of the recording head to the temperature at the time of interruption.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram of a system including a recording device and its host computer according to a first embodiment of the present invention.

In FIG. 1, 101 and 103 are respectively a host computer and an interface similar to those explained in FIG. 7, and 105 is an inkjet printer. It can be done.

110 is a driver that drives the recording head based on drive data transferred from the interface 103; 11]
is a CPU that controls each part of the printer 105;
IIIA is a RAM having an area used as a work area for control processing by the CPU Il, a counter area for counting standby time (to be described later), and a register for storing detected temperature, and 111B is for processing to be described later in FIG. This is a ROM that stores procedures, tables, etc. that will be described later in FIG. 4. 112 is a so-called bubble jet type recording head, and 113 is a head temperature detection means such as a thermistor. Reference numeral 114 denotes a carriage drive motor for driving a carriage on which the print head 112 is mounted and performs scanning movement for printing, and performs a predetermined drive even during idle ejection at a predetermined position, which will be described later. Further, 102 is an image data signal, 104 is a drive data signal, 120 is an interface status instruction signal, 121 is a head drive signal, 122 is an ejection command signal, 123 is a head temperature signal, and 124 is a carriage movement signal.

FIGS. 2A and 2B are a schematic cross-sectional view and a perspective view of essential parts, respectively, of the above-mentioned inkjet printer.

In these figures, a recording head 112 is mounted on a carriage 6 and can perform scanning movement for recording, and can also be moved to a predetermined position for idle ejection as described later. During these movements, the carriage 6 is guided along its movement path by a guide 6A and is moved by a driving force from a carriage motor (not shown) transmitted via a belt 6B. Note that the recording head 11
2 consists of four print heads corresponding to yellow, magenta, cyan, and black inks, as shown in Figure 2 (B), and each print head runs in the sub-scanning direction (perpendicular to the scanning direction). For example, it has 64 discharge ports.

Reference numeral 160 denotes an ink receiver provided in an area adjacent to the recording area of the recording head 112 so as to be able to face each ejection port of the recording head 112, and the portion that receives the ink ejected from the recording head is, for example, an ink absorber. The ink formed by or received by the body may be guided to a waste ink tank (not shown). As will be described later, after the recording standby, the recording head 112 performs so-called idle ejection at a position facing the ink receiver 112 to increase the temperature of the ink in each liquid path. Note that during idle ejection, instead of using the dedicated ink receiver 160 as described above, a caving member or the like related to ejection recovery processing may be used.

A platen 9 for regulating the recording surface of the recording paper 2 extends in a range that can face the ejection port forming surface of the recording head 112. After the recording paper 2 is conveyed a predetermined amount, it is cut into a single sheet, but before recording is performed, it is stored in the form of a roll paper 20 at a predetermined position in the printer 105. In response to a recording operation, one end of the roll paper 20 is fed to a recording area by a paper feed roller 3, and in the recording area, the paper is conveyed while the recording surface is regulated by a pair of upstream conveyance rollers 4 and downstream conveyance rollers 8, respectively. Ru. By sequentially repeating this conveyance and scanning movement by the carriage 6, the recording head 112 discharges ink and records on the recording paper 2. When the portion of the recording paper 2 corresponding to the trailing edge of one page is conveyed to the position of the cutter 5, the recording paper 2 is removed by rotating this cutter.
is cut, and after one page of recording is completed on this recording paper, the paper is discharged to a predetermined location such as a paper discharge tray via paper guides 10 and 11.

The recording head used on the upper side is a bubble jet type recording head, as described above. FIG. 3 shows a portion of this recording head corresponding to one ejection port.

FIG. 3 is a cross-sectional view of the discharge port and the liquid path communicating therewith, 150 is a heater (electrothermal converter) made of a heat generating resistor, 151 is an electrode for supplying power to the heater 150, and these Heater 150 and electrode 15
1 is formed on a substrate such as Si.

152 is an ejection port, and 153 is ink that fills the liquid path.

In the recording head configured as above, the electrode 151
An electric pulse is applied to the heater 150 to generate heat.

This heat generation causes film boiling in the ink 153,
Ink is ejected from the ejection port 152 due to the pressure of the bubbles caused by this film boiling. When such a head performs ejection, the temperature of the ink within the liquid path, which is a portion where the heat of the heater 150 directly acts on the ejected ink, rises relatively quickly. Therefore, in order to prevent the difference in recording density after the recording standby as described above, by performing dry ejection in advance, it is possible to minimize the difference between the ink temperature in the liquid path and the temperature before the standby state. Become.

FIG. 4 is a diagram showing how many pulses of idle discharge are performed depending on the temperature before standby and the standby time. Curve F shows that when the recording head temperature immediately before the standby state is 45°C, curve G is 50°C.
℃, curve H shows the case of 40°C. In this way, when the temperature immediately before standby is high, or when the standby time is long, by performing multiple pulses of empty ejection, the temperature of the ink in the liquid path can be quickly brought close to the temperature before the standby state. This makes it possible to suppress changes in concentration as much as possible. Since the diagram shown in FIG. 4 differs depending on the structure of the head, it is desirable to obtain it in advance through experiments.

FIG. 5 is a flowchart showing the procedure of recording processing according to this example. The recording process of this example will be explained below with reference to FIG.

When the recording process is started, a predetermined amount of image data according to the memory capacity of the host computer 101 is transferred to the interface 103 from the host computer 101 in step 5501, for example, image data for five scans as explained in FIG. stand by. The transferred image data is stored in the memory of the interface 103 and converted into drive data, but when this predetermined amount of data has been transferred, the predetermined amount of data is recorded in step 5503 after this processing procedure is started. It is determined by the flag whether or not it has been completed. That is, here the eighth
This is to judge whether or not it is the first record among the records for one page shown in the figure. If the flag is 'L', it is assumed that it is the first record of one page and the process advances to step 5505. Performs recording operation for scanning.

That is, the recording head 112 is moved back and forth once in this range while facing the recording area of the recording paper 2, and ink is ejected according to the forward movement or both forward and backward movements to perform one scan of printing.

Next, in step 5507, it is determined whether recording for one page has been completed, based on the contents of a scanning number counter built into the CPU III, for example. If it is determined that printing has not ended, then in step 5509 it is determined whether printing using a predetermined amount of drive data stored in the memory within the ink face 103 has ended. For example, in the example shown in FIG. 8, the CPU determines whether recording for five scans has been completed.
This can be determined based on the contents of the counter built into III. If the determination is negative here, the processing from step 8505 onwards can be repeated.

When it is determined in step 5509 that recording of the drive data stored in the memory of the interface 103 has been completed, a flag indicating that the predetermined amount of scanning has been completed is set to °°H° in step 5511, and step 5513 In step 5515, the recording head 112 is moved to a standby position such as the home position, and at the same time, in step 5515, counting of the standby time is started. This time measurement can be performed by counting the period of a signal indicating the standby state supplied from the interface 103. Along with this process, step 5
At step 517, the recording head temperature at the end of the predetermined amount of scanning is detected and stored in RAMIIIA, after which the process returns to step 5501 and a person is in a standby state.

In step 5501, it is determined that the image data transfer to the interface 103 has been completed, and in step 5503, it is determined that the content of the flag set in step 5511 is "H", that is, recording is interrupted. If it is determined that it is in a standby state, the process advances to step 5519, where the standby time that has been counted so far is detected, and this time that has been counted is also reset. Next, in step 5521, the recording head 112 is moved to the position of the ink receiver 160 to perform idle ejection. This dry ejection is determined by referring to the daple stored in ROMIIIB and having the relationship shown in FIG. This is done by determining the number of ejections. When this idle ejection operation is completed, the process advances to step 5505 and a recording operation begins.

In the first embodiment described above, ink is actually ejected to raise the temperature of the ink in the liquid path after waiting, but in the second embodiment, a driving pulse with a voltage or pulse width that does not eject ink is used. Apply.

In the case of the bubble jet method, the heater may be damaged due to cavitation, etc. caused by the generation and disappearance of bubbles when ink is ejected. For this reason, an attempt is made to prevent the life of the recording head from decreasing as much as possible by avoiding unnecessary ink ejection as much as possible. Furthermore, in the case of the first embodiment, a means for recovering ink ejected to the idle ejection position is required, which may result in a large device configuration.

In this example, by applying a drive pulse to the heater in each liquid path to the extent that ink is not ejected, the temperature of the ink in the liquid path is quickly raised, and the concentration change before and after standby is suppressed. It is something.

In addition, the above 1. In the second embodiment, the application pulse of the discharge heater was determined according to the standby time and the head temperature before standby, but in the third embodiment, in addition to these two factors, the application pulse was determined by taking into account the environmental temperature. Determine.

In the third embodiment, as shown in FIG. 6, an environmental temperature detection means 115 is separately provided to input the environmental temperature to the CPU 111, and detect the table having the relationship as shown in FIG. Prepare for each temperature. As a result, when the environmental temperature is low, more ejection pulses can be given because the head temperature decreases during standby, and when the environmental temperature is high, fewer ejection pulses can be given.
It becomes possible to suppress concentration changes more accurately.

In the above three embodiments, an inkjet printing apparatus using a serial type printing head has been described, but an inkjet printing apparatus using a full line type printing head may also be used.

Further, the present invention can be practiced not only with an inkjet recording head such as a bubble jet type but also with any type of recording head such as thermal transfer in which the temperature rises during driving.

Furthermore, the standby state does not necessarily mean the time for receiving transferred data, but rather enters the standby state during printing for other purposes, such as performing head recovery operations such as suctioning ink or wiping the ejection surface during printing. The present invention can be applied to any type of material.

In addition, not only the number of drive pulses applied to the head may be varied depending on the standby time, but also the voltage and pulse width of the drive pulses may be varied.

(Others) The present invention brings about excellent effects particularly in a bubble jet type recording head and recording apparatus, which is proposed by Canon Co., Ltd. among inkjet recording types. This is because such a system can achieve higher recording density and higher definition.

As for typical configurations and principles thereof, it is preferable to use the basic principles disclosed in, for example, US Pat. No. 4,723,129 and US Pat. No. 4,740,796. This method can be applied to both the so-called on-demand type and continuous type, but especially in the case of the on-demand type, it is necessary to arrange the liquid (ink) in accordance with the sheet and liquid path that hold it. The electrothermal converter that is
Generating thermal energy in the electrothermal transducer by applying at least one drive signal corresponding to recorded information and providing a rapid temperature rise exceeding nucleate boiling to produce film boiling on the thermally active surface of the recording head. As a result, bubbles in the liquid (ink) can be formed in a one-to-one correspondence with this drive signal, which is effective. The growth and contraction of the bubble causes liquid (ink) to be ejected through the ejection opening to form at least one droplet. If this drive signal is in the form of a pulse, bubble growth and contraction will occur immediately and appropriately.
Particularly responsive liquid (ink) ejection can be achieved,
More preferred. This pulse-shaped drive signal is described in U.S. Pat. Nos. 4,463,359 and 4,345,262.
Those described in the specification are suitable. Furthermore, if the conditions described in US Pat. No. 4,313,124 concerning the invention regarding the temperature increase rate of the heat acting surface are adopted, even more excellent recording can be performed.

The configuration of the recording head includes, in addition to the combination configuration of ejection ports, liquid paths, and electrothermal converters (straight liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned specifications, a heat acting section. The present invention also includes configurations using US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose configurations in which the wafer is placed in a bending region. In addition, Japanese Patent Application Laid-Open No. 1989-5 discloses a configuration in which a common slit is used as a discharge part of a plurality of electrothermal converters.
No. 9-123670 and Japanese Patent Application Laid-Open No. 59/1989 which discloses a configuration in which a discharge portion is made to correspond to an opening that absorbs pressure waves of thermal energy.
The effects of the present invention are also effective even if the structure is based on the publication No.-138461. That is, regardless of the form of the recording head, according to the present invention, recording can be performed reliably and efficiently.

Furthermore, 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 that can be recorded by a recording apparatus.

Such a recording head may be constructed by combining a plurality of recording heads to shorten the length, or may be constructed as a single recording head integrally formed.

In addition, even with the serial type shown above, the recording head is fixed to the device body, or by being attached to the device body, electrical connection to the device body and ink supply from the device body are possible. The present invention is also effective when using a replaceable deep-type recording head or a cartridge-type recording head in which an ink tank is integrally provided in the recording head itself.

Further, it is preferable to add recovery means for the recording head, preliminary auxiliary means, etc. provided as a configuration of the recording apparatus to the present invention, because the effects of the present invention can be further stabilized. Specifically, these include capping means for the recording head, cleaning means, pressure or suction means, preheating means using an electrothermal transducer or another heating element, or a combination thereof; It is also effective to perform a preliminary ejection mode in which ejection is performed separately from printing in order to perform stable printing.

In addition, regarding the type and number of recording heads installed, for example, in addition to one type that corresponds to single-color ink, there is also a plurality of recording heads that correspond to multiple inks with different recording colors and densities. It may be something that can be done. That is, for example, the recording mode of the recording apparatus is not limited to a recording mode for only a mainstream color such as black, but may also be a recording mode in which the recording head is configured integrally or in a combination of multiple colors, The present invention is also extremely effective for devices equipped with at least one full color by color mixture.

Additionally, in the embodiments of the present invention described above,
Although ink is described as a liquid, it is an ink that solidifies at room temperature or below, but softens or liquefies at room temperature, or in an inkjet method, the ink itself is
Generally, the temperature is adjusted within the range of 0°C or more and 70°C or less so that the viscosity of the ink is within the stable ejection range, so even if the ink is in a liquid state when the recording signal is applied. Bye. In addition, the temperature rise caused by thermal energy can be actively prevented by using the energy to change the state of the ink from a solid state to a liquid state, or the ink that solidifies when left standing is used to prevent ink evaporation. In any case, the ink is liquefied by applying heat energy in accordance with the recording signal, and the liquid ink is ejected, or the ink already begins to solidify by the time it reaches the recording medium. The present invention is also applicable when using ink that is liquefied only by thermal energy. The ink used in this case is
Publication No. 4-56847 or JP-A-60-71260
As described in the above publication, the porous sheet may be held in a liquid or solid state in the recesses or through-holes of the porous sheet, facing the electrothermal converter. In the present invention, the most effective method for each of the above-mentioned inks is to implement the above-mentioned film boiling method.

In addition, the inkjet recording apparatus of the present invention may take the form of an image output terminal for information processing equipment such as a computer, a copying apparatus combined with a reader, etc., or a facsimile apparatus having a transmitting/receiving function. It may also be something.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, a print head drive signal for temperature control when restarting recording is determined according to the print head temperature at the time of recording interruption and the interruption time, and this signal is used in advance to control the temperature when recording is resumed. Since the recording head is driven, for example, in the case of an inkjet recording head, the higher the temperature at the time of interruption, or the longer the interruption time, the greater the number of ejection pulses and the pulse width of the drive pulse. With the generated drive signal, it is possible to quickly restore the temperature of the recording head to the temperature at the time of interruption.

As a result, the difference in density between images recorded before and after standby for recording can be suppressed as much as possible, and deterioration in image quality due to standby for recording can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a control configuration of an inkjet recording apparatus according to a first embodiment of the present invention, and FIGS. 2(A) and (B) are respective schematic sectional views of the inkjet recording apparatus according to an embodiment of the present invention. and a schematic perspective view, FIG. 3 is a schematic cross-sectional view of an ink liquid path in an inkjet recording head according to an embodiment of the present invention, and FIG. A diagram showing the relationship with the pulse for each head temperature before recording interruption, FIG. 5 is a flowchart showing the recording processing procedure according to the first embodiment of the present invention, and FIG. 6 is a diagram according to the third embodiment of the present invention. FIG. 7 is a block diagram showing the configuration of a computer using the inkjet recording device as an image information recording means; FIG. 8 is a block diagram showing the configuration of a computer using the inkjet recording device as an image information recording means; FIG. FIG. 9, a schematic diagram of recording paper, is a diagram showing that a large density difference occurs before and after recording is interrupted in a conventional recording apparatus. 101...Host computer, 103...Interface, 110...Head driver, 111...CPU. 111A...RAM, 111B...ROM. 112... Recording head, 113... Head temperature detection means, 115... Environmental temperature detection means, 160... Ink receiver. Fig. Hill resistance time (sec) Fig. - +X

Claims (1)

[Claims] 1) A recording apparatus having a standby mode in which recording operation is interrupted during recording and stands by, comprising: a recording head for recording on a recording medium; and head temperature detection means for detecting the temperature of the recording head. a storage means for storing temperature information detected by the head temperature detection means when recording is interrupted in the standby mode; a standby time clock means for timing the interruption time of the recording operation; and when the recording operation is resumed after the interruption. 2) head drive control means for providing the recording head with a drive signal corresponding to the temperature stored in the temperature storage means and the interruption time measured by the standby time clock means; 2) the head drive control means is configured to control the temperature and the 2. The printing apparatus according to claim 1, wherein a drive signal is applied in accordance with the environmental temperature of the print head in addition to the interruption time. 3) The recording head uses thermal energy to cause film boiling in the ink, ejects the ink as bubbles grow due to the film boiling, and records on the recording medium with the ink. The recording device according to claim 1 or 2, wherein: