JP2960516B2 - Image recording device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus, and more particularly, to an image recording apparatus having a standby mode in which recording is interrupted during recording.

[Conventional technology]

As this type of recording apparatus, conventionally, digital recording apparatuses such as an ink jet recording method and a thermal transfer recording method are well known.

In particular, an ink jet recording apparatus has advantages such as easy colorization, and is widely used as, for example, a computer graphics output apparatus.

FIG. 7 is a block diagram showing a configuration when the ink jet recording apparatus is used as an output device in computer graphics. In FIG. 7, image data of the host computer 101 is transmitted through an interface 103.
Is stored in a memory (not shown) in 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 recording 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 possessed by the host computer sometimes exceeds this capacity. In such a case, the host computer may transfer the data corresponding to the capacity of the memory of the interface, and after completing the recording with the data, transfer the remaining data and perform the recording based on the remaining data. it can. At this time, after printing is performed based on the data from the interface, the printer interrupts the conveyance of the storage paper and the driving of the print head, and waits for the next data to be transferred. As a result, the image recording system having the above-described configuration can deal with an amount of image data larger than the memory capacity of the interface, and perform recording based on the image data.

Incidentally, in the case of a printing apparatus having a standby mode in which such a printing operation is interrupted, there are the following problems.

That is, the density of a recorded image may change discontinuously before and after standby. This is not preferable from the viewpoint of recording stability, and in particular, when the above-described density change occurs on the same recording paper, image quality is significantly impaired.

FIG. 8 is a schematic view of a recording sheet in a case where the above-mentioned standby state occurs during recording on one recording sheet. In FIG. 8, it is assumed that the recording radiation of the recording head, that is, the length of the range in which the ejection openings are arranged in the ink jet recording head is d, and the image is recorded by scanning in the X direction in FIG. Further, an image for a total of 24 scans can be recorded on one sheet of recording paper shown in FIG.
It is assumed that there is only a capacity for 5 scans.

In such a case, first, recording is continuously performed on the portion indicated by A in the figure, and then, a standby state is entered until the image data of the portion indicated by B is transferred. After the transfer is completed, recording is continuously performed on the portion B, and then the image forming apparatus 1 enters the standby state again until the image data of the portion C is transferred. After the transfer is completed, recording is continuously performed on the portion C, and recording for one recording sheet is completed.

In general, the temperature of a recording head increases when recording is continuously performed. For example, in an ink jet type recording head, a discharge energy generating element for discharging ink generates thermal energy with discharge to raise the temperature of the head. Even in a thermal transfer type recording head, the temperature of the head rises due to the heat generated by the heating elements.
When the temperature rises in this manner, for example, in an ink jet recording head, the viscosity of the ink decreases, the ink ejection amount increases, and the recording density increases. In the thermal transfer method, the amount or area of the ink to be transferred increases, and the density similarly increases. However, once the printer enters a state of waiting for printing, the temperature drops, and the printing density may be lowered immediately after printing. This phenomenon can be seen in any print head, but particularly in a so-called bubble jet print head in which a heater generates heat to cause ink to boil and discharge with the pressure of bubbles generated by the ink, even in an ink jet method. Notable.

FIG. 9 shows a change in recording density when performing image recording as shown in FIG.

As shown in FIG. 9, during continuous recording, the temperature of the recording head rises little by little and the density rises with this, so that the density change is not conspicuous. When the recording standby state indicated by the time points D and E is intervened, the density changes rapidly as the temperature of the recording head decreases. As a result, there arises a problem that a density difference between portions recorded before and after such a standby state in a recorded image becomes very noticeable.

On the other hand, conventionally, for example, in order to maintain a constant head temperature before and after such a standby state, the recording head is generally provided with a temperature detecting means such as a thermistor and a heater for maintaining the temperature, and the recording head is controlled to a temperature detected by the temperature detecting means. It is well known to control the temperature by driving a heater for keeping the temperature accordingly.

[Problems to be Solved by the Invention] However, this type of temperature control has a slow response when the temperature is rapidly changing, and causes a relatively rapid temperature change as shown at points D and E in FIG. In such a case, it is difficult to perform precise temperature control. In particular, when one print head is provided with one thermistor and heater, and it is intended to control the entire print head to a constant temperature, even if the temperature detected by the thermistor has reached a predetermined temperature, the ejection energy generating element is provided. The temperature of the ink in the liquid path, which is the place where the applied ejection energy acts on the ink, has not reached that temperature, and if printing is performed in this state, the density difference often remains. Therefore, it is necessary to raise the temperature of the ink in the liquid path directly involved in the ejection to a predetermined temperature as soon as possible, and to overcome such a phenomenon.

The present invention has been made in view of the above problems,
The purpose is to set the recording head temperature and the recording immediately before the interruption to the recording before the recording is resumed after the interruption of the recording in the recording apparatus having the mode in which the recording is suspended during the image recording and the recording apparatus is in the standby state. It is an object of the present invention to provide an image recording apparatus in which a recording element of a recording head is preliminarily driven in accordance with an interruption time or the like, thereby increasing a temperature of the recording element and suppressing a density difference before and after interruption. .

[Means for solving the problem]

Therefore, in the present invention, when recording an image by driving a recording head that performs recording using thermal energy,
In an image recording apparatus capable of temporarily interrupting and resuming a recording operation, a determination unit for determining the temporary interruption that occurs during a recording operation, a head temperature detection unit for detecting a temperature of the recording head, and the determination unit Storage means for storing the head temperature detected by the head temperature detection means when determining the temporary interruption which occurs during the recording operation; interruption time measuring means for measuring the recording interruption time; and storage in the storage means. In order to equalize the recording densities at the time of recording interruption and at the time of resuming recording according to the measured head temperature and the interruption time measured by the interruption time measuring means, the temperature of the recording head is controlled before the image recording at the time of resuming recording. And a head drive control means for providing the drive signal of

[Action]

According to the above configuration, according to the head temperature at the time of temporary interruption of recording and the interruption time, the head is driven prior to image recording so that the recording density at the time of recording interruption and at the time of recording resumption are equalized. Since the drive signal is supplied, the head temperature at the time of resuming recording can be increased to a temperature that makes the recording density equal.

〔Example〕

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

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

In FIG. 1, 101 and 103 are the same host computer and interface as described in FIG. 7, respectively, and 105 is an ink jet printer. The configuration of the ink jet printer 105 according to this example is shown below. .

Reference numeral 110 denotes a driver that drives a print head based on drive data transferred from the interface 103, 111 denotes a CPU that controls each unit of the printer 105, 111A denotes an area used as a work area for control processing by the CPU 111, and an area described below. A RAM having a counter area for counting the standby time and a register for storing the detected temperature, 111B is a ROM storing a processing procedure described later in FIG. 5, a table described later in FIG. 4, and the like. 112 is a so-called bubble jet type recording head, and 113 is a head temperature detecting 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 to perform scanning movement for printing, and also performs a predetermined drive during idle discharge at a predetermined position described later. 102 is an image data signal, 104
Is a drive data signal, 120 is an interface state instruction signal, 121 is a head drive signal, 122 is a discharge command signal, 123
Is a head temperature signal, and 124 is a carriage movement signal.

FIGS. 2A and 2B are a schematic sectional view and a perspective view of a main part of the above-described ink jet printer, respectively.

In these figures, the recording head 112 is mounted on the carriage 6 and can perform scanning movement for recording, and can move to a predetermined position for idle discharge as described later. In these movements, the carriage 6 is moved by a driving force from a carriage motor (not shown) transmitted via a belt 6B while being guided along this movement path by a guide 6A. As shown in FIG. 2 (B), the recording head 112 includes four recording heads corresponding to yellow, magenta, cyan, and black inks, and each recording head is in the sub-scanning direction (perpendicular to the scanning direction). ), For example, 64 discharge ports.

Reference numeral 160 denotes an ink receiver provided in a region adjacent to the recording region of the recording head 112 so as to be able to face each of the ejection ports of the recording head 112, and a portion for receiving ink ejected from the recording head is, for example, an ink absorber. Can be formed so as to guide the ink formed or received together with the ink to a waste ink tank (not shown). After the recording head 112 waits for recording as described later, the recording head 112
A so-called idle discharge is performed at a position facing 12 to raise the temperature of the ink in each liquid path. It should be noted that a capping member or the like related to the ejection recovery process may be used for the idle ejection without using the above-described dedicated ink receiver 160.

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 by a predetermined amount, the recording paper 2 is cut into a single sheet. Before recording, the recording paper 2 is stored at a predetermined position of the printer 105 in the form of roll paper 20. One end of the roll paper 20 is sent to the recording medium by the paper feed roller 3 according to the recording operation, and is conveyed in the recording area while the recording surface is regulated by the pair of the upstream conveyance roller 4 and the downstream conveyance roller 8 respectively. You. By sequentially repeating this conveyance and the scanning movement by the carriage 6, the recording head 112 ejects the ink and prints the recording paper 2.
To record. When a portion corresponding to the rear end of one page of the recording paper 2 is conveyed to the position of the cutter 5, the recording paper 2 is cut by rotating the cutter, and then recording of one page on the recording paper is completed. Then, the paper is discharged to a predetermined portion such as a paper discharge tray via the paper guides 10 and 11.

The recording head used in the above example is a bubble jet type recording head as described above. FIG. 3 shows a portion corresponding to one ejection port of the recording head.

FIG. 3 is a cross-sectional view of a discharge port and a liquid passage communicating with the discharge port. Reference numeral 150 denotes a heater (electrothermal converter) formed of a heating resistor, and 151 denotes an electrode for supplying electric power to the heater 1590. The heater 150 and the electrode 151 are formed on a substrate such as Si. 152 is an ejection port, and 153 is ink filled in the liquid path.

In the recording head having the above configuration, the electrode 151
The heater 150 is heated by applying an electric pulse to the heater 150. This heat generation causes film boiling in the ink 153, and the ink is discharged from the discharge port 152 by the pressure of the bubble due to the film boiling. When discharging with such a head, the heater
The temperature of the ink in the liquid passage, which is a portion where the heat of 150 directly acts on the ink to be discharged, rises relatively quickly. For this reason, it is possible to minimize the difference between the ink temperature in the liquid path and the temperature before the standby state by performing the idle discharge in advance to prevent the occurrence of the print density difference after the print standby as described above. Become.

FIG. 4 is a diagram showing how many pulses of idle discharge are performed according to the temperature and the standby time before the standby. Curve F is 50 ° C. when the print head temperature immediately before the standby state is 45 ° C.
, Curve H shows the case at 40 ° C. As described above, when the temperature immediately before the standby is high, or when the standby time is long, the idle ejection of a large number of pulses is performed, whereby the temperature of the ink in the liquid path can be quickly brought close to the temperature before the standby state, It is possible to minimize the change in concentration. Since the diagram shown in FIG. 4 differs depending on the structure of the head, it is desirable to obtain the diagram in advance by an experiment.

FIG. 5 is a flowchart showing the procedure of the recording process according to this example. Hereinafter, the recording process of this example will be described with reference to FIG.

When the recording process is started, a predetermined amount of image data corresponding to the memory capacity, for example, image data for five scans described in FIG. 8 is transferred from the host computer 101 to the interface 103 in step S501. stand by. The transferred image data is stored in the memory of the interface 103 and is converted into drive data.When the transfer of the predetermined amount is completed, the recording of the predetermined amount is performed in step S503 after the present processing procedure is started. It is determined by the flag whether or not it has been performed. That is, here, 1 shown in FIG.
It is to determine whether or not the printing is the first printing of the pages. If the flag is "L", it is determined that the printing is the first printing of one page, and the process proceeds to step S505 to perform the printing operation for one scan. In other words, the recording head 112 makes one reciprocation in this area while opposing the recording area of the recording paper 2, and performs ink for one scan by ejecting ink according to the forward operation or both the reciprocating operations during this period.

Next, in step S507, for example, it is determined whether or not the recording of one page has been completed based on the content of the scanning number counter incorporated in the CPU 111. If it is determined that the recording has not been completed, it is next determined in step S509 whether or not the recording with the predetermined amount of drive data stored in the memory in the interface 103 has been completed. For example, in the example shown in FIG.
Whether or not the printing for the scan has been completed can be determined based on the content of a counter built in the CPU 111. Here, in the case of a negative determination, the processing from step S505 is repeated.

If it is determined in step S509 that the recording of the drive data built in the memory of the interface 103 has been completed,
In step S551, a flag indicating that the predetermined amount of scanning has been completed is set to "H", and in step S513, the recording head 112 is moved to a standby position such as a home position, and at the same time, timing of the standby time is started in step S515. I do. This timing can be performed by counting the period of the signal indicating the standby state supplied from the interface 103. Along with this processing, in step S517, the printhead temperature at the end of the predetermined amount of scanning is detected and stored in the RAM 111A, and then the process returns to step S501 to enter a standby state.

In step S501, it is determined that the transfer of the image data to the interface 103 has been completed. Further, in step S503, when it is determined that the content of the flag set in step S511 is "H", that is, the recording is interrupted and the standby is performed. If it is determined that the state has been performed, the process proceeds to step S519.
Then, the standby time measured so far is detected, and the measured time is reset together therewith. Next, in step S521, the print head 112 is moved to the position of the ink receiver 160 to perform idle discharge. This idle discharge is performed by referring to the table stored in the ROM 111B and having the relationship as shown in FIG.
This is performed by determining the number of idle ejections based on the temperature of the print head before standby detected in S517. Upon completion of the idle discharge operation, the process proceeds to step S505, and starts a recording operation.

In the first embodiment, the ink is actually ejected in order to raise the temperature of the ink in the liquid path after the standby.
In the second embodiment, a drive pulse having a voltage or a pulse width that does not discharge ink is applied.

In the case of the bubble jet method, the heater may be damaged due to cavitation or the like accompanying the generation and disappearance of bubbles during ink ejection. For this reason, an attempt is made to prevent a reduction in the life of the recording head as much as possible by minimizing unnecessary ink ejection. Further, in the case of the first embodiment, a unit for collecting the ink discharged to the idle discharge position is required, and the apparatus configuration may become large.

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 density change before and after standby is suppressed. Things.

Further, in the first and second embodiments, the application pulse of the discharge heater is determined in accordance with the standby time and the head temperature before the standby. In the third embodiment, the environmental temperature is determined in addition to the two. The applied pulse is determined in consideration of the above.

In the third embodiment, as shown in FIG. 6, an environmental temperature detecting means 115 is provided to input an environmental temperature to the CPU 111, and to detect a table having a relationship as shown in FIG. Prepare each time. As a result, when the ambient temperature is low, the head temperature drop during standby is large, so that more ejection pulses can be given, and when the ambient temperature is high, fewer ejection pulses can be given, and the density change can be more accurately performed. It can be suppressed.

In the above three embodiments, an ink jet recording apparatus using a serial type recording head has been described. However, a full line type recording head may be used.

In addition, the present invention can be implemented not only with an ink jet recording head of a bubble jet system or the like, but also with any other type of recording head, such as thermal transfer, whose temperature rises during driving.

Further, the standby state is not necessarily the time for receiving the transfer data, and enters the standby state during printing for another purpose such as performing a head recovery operation such as ink suction or wiping of the ejection surface during printing. However, the present invention can be applied to any case.

In addition, the number of drive pulses applied to the head may be varied according to the standby time, and the voltage or pulse width of the drive pulse may be changed.

(Others) The present invention brings about an excellent effect particularly in a bubble jet type recording head and a recording apparatus proposed by Canon Inc. among ink jet recording methods. 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 any of the so-called on-demand type and continuous type. In particular, in the case of the on-demand type, it is arranged corresponding to the sheet or liquid path holding the liquid (ink). Applying at least one drive signal corresponding to recording information and providing a rapid temperature rise exceeding nucleate boiling to the electrothermal transducer, thereby causing the electrothermal transducer to generate heat energy, and 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 immediately and appropriately performed, and therefore, the ejection of the 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. If the conditions described in U.S. Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface described above 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, The present invention also includes a configuration using U.S. Pat. Nos. 4,458,333 and 4,459,600, which disclose a configuration in which is disposed in a bending region. 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 Japanese Patent Application Laid-Open No. 59-138461, which discloses a configuration corresponding to a discharge unit. That is,
This is because, according to the present invention, 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 combining a plurality of recording heads, or a configuration as a single recording head that is integrally formed.

In addition, even with the serial type printer as in the above example, the recording head fixed to the main unit or attached to the main unit enables electrical connection with the main unit and supply of ink from the main unit. The present invention is also effective when a replaceable chip type print head or a cartridge type print head having an ink tank provided integrally with the print head itself is used.

Further, it is preferable to add recovery means for the recording head, preliminary auxiliary means, and the like provided as a configuration of the storage device 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. It may be done. That is, for example, the printing mode of the printing apparatus is not limited to the printing mode of only the mainstream color such as black, but may be any of integrally forming the printing head or a combination of a plurality of printing heads. The present invention is also extremely effective for an apparatus provided with at least one of full colors by color mixture.

In addition, in the embodiments of the present invention described above, the ink is described as a liquid. However, an ink that solidifies at or below room temperature and softens or liquefies at room temperature, or the ink itself in an inkjet method. In general, the temperature is controlled within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. I just need. In addition, the temperature rise due to thermal energy can be positively prevented by using it as energy for changing the state of the ink from a solid state to a liquid state, or ink that solidifies in a standing state to prevent evaporation of the ink can be used. In any case, the ink is liquefied by the application of the thermal energy according to the recording signal, and the ink is liquefied, and the liquid ink is discharged. The present invention is also applicable to a case where an ink that liquefies for the first time by energy is used. The ink in such a case is disclosed in
No. -56847 or JP-A-60-71260, while being held as a liquid or solid substance in a porous sheet recess or through hole, facing the electrothermal converter. It is good also as a form. In the present invention,
The most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, as the form of the ink jet recording apparatus of the present invention, in addition to the one used as an image output terminal of an information processing device such as a computer, a copier combined with a reader or the like, and a facsimile apparatus having a transmission / reception function are searched for. Or the like.

〔The invention's effect〕

As apparent from the above description, according to the present invention, according to the head temperature at the time of temporary interruption of recording and the interruption time, the image density at the time of recording interruption and at the time of recording resumption are made equal to each other. Since the drive signal for driving the head is given prior to the recording, the head temperature at the time of resuming the recording can be raised to a temperature at which the recording density is equalized.

As a result, a difference in density between images and the like printed before and after the recording standby can be added as much as possible, and deterioration of image quality due to the recording standby can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a control configuration of an ink jet recording apparatus according to a first embodiment of the present invention, and FIGS. 2A and 2B are schematic cross-sectional views of the ink jet recording apparatus according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of an ink passage in an ink jet recording head according to an embodiment of the present invention. FIG. 4 is a table showing the contents of a standby time and a discharge according to the embodiment of the present invention. FIG. 5 is a diagram showing a relationship with a pulse for each head temperature before recording interruption, FIG. 5 is a flowchart showing a recording processing procedure according to the first embodiment of the present invention, and FIG. 6 is a third embodiment of the present invention. FIG. 7 is a block diagram illustrating a control configuration of the inkjet recording apparatus. FIG. 7 is a block diagram illustrating a configuration of a computer using the inkjet recording apparatus as image information recording means. Fig. 9 is a schematic diagram of a recording sheet for explaining a recording mode in Fig. 9; Fig. 9 is a diagram showing that a large density difference occurs before and after the interruption of recording 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 detecting means, 115: Environment Temperature detection means, 160: Ink receiver.

Claims (5)

(57) [Claims] An image recording apparatus capable of temporarily suspending and resuming a recording operation when an image is recorded by driving a recording head that performs recording using thermal energy. Determining means for determining the temporary interruption, head temperature detecting means for detecting the temperature of the recording head, and when the determining means determines the temporary interruption occurring during the recording operation, the head temperature detecting means Storage means for storing the detected head temperature; interruption time timer means for measuring a recording interruption time; recording in accordance with the head temperature stored in the storage means and the interruption time measured by the interruption time timer means. Head drive control for providing a drive signal for temperature control to the printhead prior to image recording at the time of resuming recording so that the recording density at the time of interruption and at the time of resuming recording are equalized. Image recording apparatus comprising: the stage, a. 2. The apparatus according to claim 1, further comprising an environmental temperature detecting means for detecting an environmental temperature, wherein said head drive control means further controls said recording head to control a temperature in accordance with the environmental temperature detected by said environmental temperature detecting means. The image recording apparatus according to claim 1, wherein a driving signal is provided. 3. The recording head according to claim 2, wherein the recording head utilizes thermal energy to cause film boiling in the ink, ejects the ink along with the growth of bubbles due to the film boiling, and performs recording on a recording medium using the ink. The image recording device according to claim 1 or 2, wherein 4. An image recording apparatus according to claim 3, wherein said head drive control means supplies an idle ejection signal to said recording head as a driving signal for said temperature control. 5. The image recording apparatus according to claim 3, wherein said head drive control means supplies a drive pulse to the printhead as a drive signal for controlling the temperature, to such an extent that ink is not ejected. apparatus.