EP0418818A2

EP0418818A2 - Ink-jet recording apparatus and temperature control method therefor

Info

Publication number: EP0418818A2
Application number: EP90117934A
Authority: EP
Inventors: Naoji Otsuka; Kentaro Yano; Hitoshi Sugimoto
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 1989-09-18
Filing date: 1990-09-18
Publication date: 1991-03-27
Anticipated expiration: 2010-09-18
Also published as: ATE165048T1; CA2025506A1; DE69032238D1; EP0418818A3; CA2025506C; CN1051884A; DE69032238T2; AU635770B2; CN1191931C; AU6263590A; EP0418818B1; CN1064598C; SG84552A1; CN1359798A; SG44735A1

Abstract

An ink-jet recording apparatus for discharging an ink droplet from a recording head to perform recording includes a heating element array for heating the recording head, a temperature sensor for measuring an ambient temperature, a timer for measuring a time associated with a temperature variation of the recording head during a recording operation, and a control unit for controlling an energy supplied to the heating element array on the basis of the ambient temperature measured by the temperature sensor and the time measured by the timer.

Description

complicated adjustment operation for adjusting a variation in temperature sensor of the recording head in an adjustment process, or mounting a temperature sensor which is measured and ranked in a main body, and correcting it using an adjustment selection switch.
These operations considerably increase manufacturing cost, and impair operability. An increase in signal processing volume caused by these operations, and a considerable increase in processing volume of an MPU caused by closed-loop control itself exert a heavy load on design of a compact or portable printer main body apparatus.

(2) Countermeasure against electrostatic noise

Since a disposable head is an expendable supply, a user frequently attaches or detached it to or from a main body. For this reason, contacts of the main body are always exposed.
Since the output from the temperature sensor is directly supplied to a circuit on a printed circuit board of the main body through a carriage and a flexible wiring, a temperature measurement circuit is very weak against electrostatic noise. Since a compact or portable printer cannot have a sufficient shield effect in its housing, it is further weak against electrostatic noise.
Therefore, in a conventional temperature detection method, an electrostatic shield, and parts as a countermeasure against electrostatic noise must be added at respective portions for only a single temperature sensor, thus considerably disturbing a compact structure, a decrease in cost, and high image quality.

SUMMARY OF THE INVENTION:

It is a principal object of the present invention to provide an ink-jet recording apparatus which can control a temperature of a recording head to fall within a desired range without arranging a temperature sensor in the recording head, and a temperature control method therefor.
It is another object of the present invention to provide an ink jet recording apparatus which can control a temperature of a recording head to fall within a desired range even when a print rate is changed, and a temperature control method therefor.
It is still another object of the present invention to provide an ink-jet recording apparatus which can control a temperature of a recording head to fall within a desired range even when a difference between a temperature in the recording apparatus and a temperature of the recording head occurs, and a temperature control method therefor.
It is still another object of the present invention to provide an ink-jet recording apparatus which can prevent a temperature of a recording head from being increased to an abnormal high temperature, and a temperature control method therefor.
In order to achieve the principal object, according to a preferred aspect of the present invention, there is provided an ink-jet recording apparatus for causing a recording head to discharge an ink droplet to perform recording, comprising:

heat means for heating the recording head;
temperature measurement means for measuring an ambient temperature;
timer means for measuring a time associated with a temperature variation of the recording head in association with a recording operation; and
control means for controlling an energy to be supplied to the heat means on the basis of the ambient temperature measured by the temperature measurement means and the time measured by the timer means.

In order to achieve another object, according to another preferred aspect of the present invention, there is provided an ink-jet recording apparatus for causing a recording head to discharge an ink droplet to perform recording, comprising:

heat means for heating the recording head;
temperature measurement means for measuring an ambient temperature;
print rate measurement means for measuring a print rate in a predetermined time of the recording head; and
control means for controlling an energy to be supplied to the heat means on the basis of the ambient temperature measured by the temperature measurement means and the print rate measured by the print rate measurement means.
Fig. 28 is a timing chart showing output timings of temperature control pulses;
Fig. 29'is a flow chart showing temperature control according to the fourth embodiment of the present invention;
Fig. 30 is a graph showing an equilibrated temperature of a recording head according to a print rate;
Fig. 31 is a graph showing an increase and a decrease in temperature of the recording head according to the print rate;
Figs. 32 and 33 are flow charts showing temperature control according to the fifth embodiment of the present invention;
Fig. 34 is a perspective view showing an ink-jet recording apparatus suitable for carrying out temperature control according to the sixth embodiment of the present invention;
Fig. 35 is a partial perspective view showing a structure of a recording head shown in Fig. 34;
Fig. 36 is a graph showing the relationship between a temperature of the recording head shown in Fig. 34 and a temperature of a power transistor for driving a discharge heater;
Fig. 37 is a block diagram showing a temperature control system of the recording head shown in Fig. 34;
Fig. 38 is a partial perspective view showing a structure of a recording head for performing temperature control according to the seventh embodiment of the present invention;
Fig. 39 is a sectional view of a printed circuit board according to the seventh embodiment of the present invention;
Fig. 40 is a block diagram of a temperature control system according to the seventh embodiment of the present invention;
Figs. 41A and 41 B are sectional views of a printed circuit board used in the eighth embodiment of the present invention;
Fig. 42 is a sectional view of a printed circuit board used in the ninth embodiment of the present invention; and
Fig. 43 is a block diagram of a control system according to the ninth embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS :

Figs. 2 to 6 are views for explaining an ink-jet unit IJU, an ink-jet head IJH, an ink tank IT, an ink-jet cartridge IJC, an ink-jet recording apparatus main body IJRA, and a carriage HC, and the relationship among these components. The arrangement of these portions will be described below with reference to Figs. 2 to 6.
The ink-jet cartridge IJC in this embodiment has an increased ink storage ratio, as can be seen from the perspective view of Fig. 3, and has a shape in which the distal end portion of the ink-jet unit IJU slightly projects from the front surface of the ink tank IT. The ink-jet cartridge IJC is fixed and supported by a positioning means and electrical contacts (to be described later) of the carriage HC (Fig. 5) placed on the ink-jet recording apparatus main body IJRA, and is of a disposable type which can be detachable from the carriage HC. Since Figs. 2 to 6 of this embodiment show arrangements to which various inventions which have been made in establishment of the present invention are applied, the overall arrangement will be described below while briefly explaining these arrangements.

(i) Arrangement of Ink-jet Unit IJU

The ink-jet unit IJU is a bubble-jet type unit for performing recording using an electrothermal conversion element for generating a heat energy for causing film boiling of an ink according to an electrical signal.
In Fig. 2, a heater board 100 is prepared by forming a plurality of electrothermal conversion element arrays (discharge heater), a temperature control heater, and AI electrical wirings for supplying an electric power to these heaters on an Si substrate by a film formation technique. A wiring circuit board 200 is arranged for the heater board 100, and has wirings corresponding to those of the heater board 100 (e.g., these wirings are connected by wire bonding), and pads 201, located at the end portions of these wirings, for receiving electrical signals from the apparatus main body.
A grooved top plate 1300, on which partition walls for dividing a plurality of ink paths, a common ink chamber, and the like are arranged, is formed by integrally molding an ink reception port 1500 for receiving an ink supplied from the ink tank and guiding it to the common ink chamber, and an orifice plate 400 having a plurality of discharge ports. As a material for integrally molding these components, polysulfone is preferable, but other molding resin materials may be used.
surface of the rear portion. The partial ribs 2301 and 2302 are similarly formed on the inner surface of the lid member 1100 on the corresponding extending lines of the ribs 2300, but are divided unlike the ribs 2300 to increase an air space as compared to the ribs 2300. Note that the partial ribs 2301 and 2302 are dispersed on a surface portion 1/2 or less the entire surface of the lid member 1100. With these ribs, an ink in a corner area farthest from the ink supply port 1200 of the ink absorber can reliably guided toward the supply port 1200 by a capillarity force while being stabilized. The air communication port 1401 is formed in the lid member to cause the interior of the cartridge to communicate with outer air. A waterproof member 1400 is arranged inside the air communication port 1401 to prevent an ink from leaking from the air communication port 1401.
An ink storage space of the ink tank IT has a rectangular shape, and its long side corresponds to a side surface. Therefore, the above-mentioned arrangement of the ribs are particularly effective. When the storage space has a long side parallel to the moving direction of the carriage, or has a cubic shape, the ribs are formed on the entire lid member 1100 to stabilize ink supply from the ink absorber 900. In order to store an ink in a limited space as much as possible, a cubic shape is suitable. However, in order to efficiently use the stored ink for recording, as described above, it is important to form ribs capable of performing the above-mentioned operation on two surface regions adjacent to the corner portion. Furthermore, the ribs 2301 and 2302 on the inner surface of the ink tank IT in this embodiment are arranged at an almost uniform distribution with respect to the direction of thickness of the cubic ink absorber 900. This structure is important since it can uniform an atmospheric pressure distribution with respect to ink consumption of the overall absorber, and can make an ink residue almost zero.
Furthermore, the technical idea of the arrangement of the ribs will be described below in more detail. When an arc having a long side as a radius is drawn to have a position obtained by projecting the ink supply port 1200 of the ink tank onto the square upper surface of the cube as the center, it is important to arrange the above-mentioned ribs on a surface portion outside the arc so that an atmospheric pressure is given earlier to the absorber portion located outside the arc. In this case, the position of the air communication port 1401 of the tank is not limited to that of this embodiment as long as air can be introduced to the rib arrangement region.
In this embodiment, the ink-jet cartridge IJC has a flat rear surface portion with respect to the head to minimize a necessary space when it is assembled in the apparatus, and to maximize an ink storage amount. Therefore, the cartridge of this embodiment has an excellent structure since the apparatus can be rendered compact, and an exchange frequency of cartridges can be decreased. A projecting portion for the air communication port 1401 is formed by utilizing a rear portion of a space for integrating the ink-jet unit IJU, and the interior of the projecting portion is hollowed to form an atmospheric pressure supply space 1402 for the total thickness of the absorber 900, as described above. With this arrangement, an excellent cartridge which cannot be realized by the conventional technique can be provided.
Note that the atmospheric pressure supply space 1402 is considerably larger than a conventional one, and the air communication port 1401 is located above this space. Therefore, even if an ink is released from the absorber due to any abnormality, the atmospheric pressure supply space 1402 can temporarily store the released ink, and can reliably recover it to the absorber. Thus, an efficient cartridge can be provided.
Fig. 4 shows an arrangement of the unit IJU mounting surface of the ink tank IT. If a straight line which passes almost the center of a projecting port of the orifice plate 400 and is parallel to the bottom surface of the tank IT or the mounting reference surface for the surface of the carriage is represented by L₁, the two positioning projections 1012 to be engaged with the holes 312 of the support member 300 are located on the straight line L₁. The height of each projection 1012 is slightly smaller than the thickness of the support member 300, and this projection positions the support member 300. A pawl 2100 to be engaged with a 90 engaging surface 4002 of a positioning hook 4001 of the carriage is located on the extending line of the straight line L₁ on this drawing, so that a positioning force for the carriage acts on a surface region parallel to the reference surface including the straight line L₁. As will be described later with reference to Fig. 5, these relationships are effective since the positioning precision of only the ink tank is equivalent to that of a discharge port of the head.
Projections 1800 and 1801 of the ink tank corresponding to the fixing holes 1900 and 2000 of the support member 300 to the side surface of the ink tank are longer than the above-mentioned projections 1012, and extend through the support member 300. The projecting portions of these projections are thermally fused to fix the support member 300 on the side surface of the ink tank. When a straight line perpendicular to the above-mentioned line L₁ and passing the projection 1800 is represented by L₃ and a straight line passing through the projection 1801 is represented by L₂, since almost the center of the supply port 1200 is located on the straight line L₃, the above-mentioned projections stabilize a coupling state between the supply port 1200 and the supply pipe 2200, and can reduce a load caused by dropping or a the cartridge is mounted, the front plate receives a force perpendicular to the projection surfaces 4010. For this reason, a plurality of reinforcement ribs (not shown) along the direction of the force are arranged on the front plate 4000 on the side of the platen roller. These ribs also form head protection projections slightly projecting (about 0.1 mm) from a front surface position L₅ of the cartridge IJC when the cartridge IJC is mounted.
The electrical connecting portion support plate 4003 has a plurality of reinforcement ribs 4004 not in a direction of the above-mentioned ribs but in a direction perpendicular thereto. A sideward projecting amount is decreased from the platen side toward the hook 4001. This also serves to provide a function of inclining the cartridge mounting position, as shown in Fig. 5.
The support plate 4003 has two hook-side projection surfaces 4006 for applying a force to the cartridge in a direction opposite to a direction of a force applied from the two positioning projection surfaces 4010 to the cartridge to form a pad contact region between these two positioning surfaces, and to uniquely define deformation amounts of projections of the rubber pad sheet 4007, which projections correspond to the pads 2011. These positioning surfaces are in contact with the surface of the wiring circuit board 200 when the cartridge IJC is fixed at a recording position. In this embodiment, since the pads 201 of the wiring circuit board 200 are distributed to be symmetrical about the above-mentioned line Li, the deformation amounts of the projections of the rubber pad sheet 4007 can be uniformed to much stabilize contact pressures of the pads 2011. In this embodiment, the pads 201 are distributed in a 2 x 2 matrix.
The hook 4001 has an elongated hole to be engaged with a stationary shaft 4009. The hook 4001 is pivoted counterclockwise from the illustrated position by utilizing a moving space of this elongated hole, and thereafter, is moved to the left along the platen roller 5000, thereby positioning the ink-jet cartridge IJC with respect to the carriage HC. The hook 4001 may be moved in any other patterns, but may be preferably moved by, e.g., a lever. When the hook 4001 is pivoted, the cartridge IJC is moved toward the platen roller, and the positioning projections 2500 and 2600 are moved to positions where they can be brought into contact with the positioning surfaces 4010 of the front plate. When the hook 4001 is moved to the left, the 90. engaging surface 4002 is brought into tight contact with the 90^. surface of the pawl 2100 of the cartridge IJC, and the cartridge IJC is turned about the contact regions between the positioning surfaces 2500 and 4010 in the horizontal plane as the center. Finally, the pads 201 and 2011 begin to be brought into contact with each other. When the hook 4001 is held at a predetermined position, i.e., a fixing position, a complete contact state between the pads 201 and 2011, a complete surface contact state between the positioning surfaces 2500 and 4010, a two-surface contact state between the 90 engaging surface 4002 and the 90^. surface of the pawl, and a surface contact state between the wiring circuit board 200 and the positioning surfaces 4007 and 4008 are simultaneously formed, thus completing holding of the cartridge IJC with respect to the carriage HC.

(iv) Apparatus Main Body

Fig. 6 is a schematic perspective view of the ink-jet recording apparatus main body IJRA on which the above-mentioned cartridge is mounted. The carriage HC which is engaged with a spiral groove 5004 of a lead screw 5005 rotated through driving force transmission gears 5011 and 5009 in cooperation with a forward/reverse rotation of a driving motor 5013 has pins (not shown), and is reciprocally moved in directions of arrows a and b . A sheet pressing plate 5002 presses a sheet against the platen roller 5000 along the carriage moving direction. Photocouplers 5007 and 5008 serve as home position detection means for detecting the presence of a lever 5006 of the carriage HC in a corresponding region to switch, e.g., a rotational direction of the motor 5013. A member 5016 supports a cap member 5022 for capping the front surface of the recording head. A suction means 5015 draws the interior of this cap member by vacuum suction, i.e., performs a suction/recovery operation of the recording head through an opening 5023 in the cap member. A cleaning blade 5017 and a member 5019 for allowing the blade 5017 to be movable in the back-and-forth direction are supported on a main body support plate 5018. The blade is not limited to that of this embodiment, but a known cleaning blade may be applied to this embodiment, as a matter of course. A lever 5021 is used to start the suction/recovery operation, and is moved upon movement of a cam 5020 which is engaged with the carriage HC. The lever 5021 is subjected to movement control by a known transmission means such as a clutch for switching a driving force from the driving motor.
These capping, cleaning, and suction/recovery operations can be performed at their corresponding positions upon operation of the lead screw 5005 when the carriage HC reaches the home position region. However, any other means may be applied to this embodiment as long as desired operations are performed at known timings. The respective arrangements described above are excellent inventions not only solely but
Tables 1 and 2 show control parameter data tables used when the temperature control operations before and during printing are perform"ad, and these tables are stored in a ROM. In each table, "100%" represents supply of a maximum energy, and "0%" represents supply of no energy. In this embodiment, an energy supply amount is controlled according to an energization time (heating pulse width) to the temperature control heater. In the temperature control before printing, a maximum energization time is set to be about 6 sec, and in the temperature control during printing, it is set to be about 120 msec. Note that the energy supply amount may be controlled by an energization voltage in place of the energization time, or may be controlled by both the energization time and voltage.
In either of the temperature control operations before and during printing, as an ambient temperature is lower, the energy supply amount is increased to increase a temperature increase amount, so that the head temperature is closer to the target temperature. In the temperature control before printing, since it can be considered that the recording head radiates more heat as a wait time is longer, the energy supply amount is set to be large to cause the head temperature to approach the target temperature. On the other hand, in the temperature control during printing, since it can be considered that the temperature of the head is increased due to heat accumulation as a print time is longer, the energy supply amount is set to be small.
When the temperature control is performed as described above, the temperature of the recording head can be controlled to the target temperature without using conventional closed-loop control. This temperature control will be described in detail below.
Fig. 10 shows a change in actual temperature (T_H) of the recording head with respect to an ambient temperature (T_A) and a target temperature (To) when only the temperature control before printing is performed. Fig. 11 similarly shows a change in temperature of the recording head when only the temperature control during printing is performed, and
Fig. 12 shows a change in temperature of the recording head when both the temperature control operations before and during printing are performed.
Fig. 13 shows a change in temperature of the recording head caused by printing itself (self temperature increase) when only printing is performed without the temperature control.
Fig. 14 shows a change in temperature of the recording head when printing is performed with the temperature control operations before and during printing.
The temperature (T_H) of the recording head is switched at positions of 60 sec and 360 sec since the data in the temperature control data table during printing shown in Table 2 (temperature control parameter) is changed.
A thermal equilibrated temperature (T_E) shown in Figs. 11 and 12 means a temperature which can be naturally reached by only a temperature control energy on the basis of a heat capacity of the head, and is determined by data shown in Tables 1 and 2. The thermal equilibrated temperature is set to be slightly lower than the target temperature, so that the sum of the thermal equilibrated temperature and a temperature increase (self temperature increase) caused by self heating of the recording head shown in Fig. 13 corresponds to the target temperature.
The temperature control according to the first embodiment of the present invention will be described below with reference to the flow chart shown in Fig. 15. Note that a change in temperature of the recording head caused by this temperature control corresponds to Fig. 14.
When the power switch is turned on, a wait time counter and a print time counter are reset to zero to initialize the control parameters in step S101. In step S102, the control waits until a print signal is input.
When the print signal is input, an ambient temperature is read from the temperature sensor 8 on the printed circuit board 7 of the main body in step S103. In step S104, a wait time of the wait time counter is read. However, the wait time counter is reset to "0" as described above immediately after power-on. In step S105, the temperature control data table before printing (Table 1) is referred to on the basis of the ambient also moving amounts of the next and subsequent lines may be taken into consideration.
As a means for heating the recording head, a known means may be used. In place of measuring the print time, the number of print lines or the number of print characters may be counted.
As described above, according to the first embodiment, if conventional closed-loop temperature control by the temperature sensor incorporated in the recording head is not performed, a means for measuring an ambient temperature is arranged in a recording apparatus main body such as a printer, and a control software program utilizing heating/cooling thermal characteristics uniquely determined by a heat capacity of the recording head itself is employed, so that the temperature of the recording head can be controlled to a desired temperature.
In particular, when the disposable cartridge type recording head is used, a signal current from the temperature sensor of the recording head need not be detected. Thus, a variation in print performance among heads, as a major drawback of temperature control posed when the disposable type is employed, can be eliminated. Thus, a variation in print performance among heads can be eliminated, and uniform print quality can be obtained. Furthermore, since the temperature sensor can be omitted from the cartridge of the recording head as an expendable supply, a temperature sensor selection process, or a temperature sensor adjustment process so far can be omitted to greatly reduce cost. In addition, since the temperature sensor itself can be omitted, a manufacturing yield can be greatly increased to further reduce cost.
In view of an electrical circuit, a small signal current from the head need not be detected, and a countermeasure against exposure of contacts upon attachment/detachment of the disposable cartridge from the recording apparatus main body, and an electrostatic countermeasure for patterns of a flexible wiring and a printed circuit board between the recording apparatus main body and the recording head can be simplified.
The above features are particularly effective for a compact or portable recording apparatus which cannot take a sufficient countermeasure such as a shield on the casing or an electrical circuit. In addition, this also leads to a considerable cost-down effect.
The second embodiment of the present invention will be described below with reference to Figs. 17 to 21 and Tables 3 and 4.
In the second embodiment, sufficient temperature control attained by developing open-loop control of the first embodiment can be performed even in a recording method such as a bubble-jet method in which heat generation or radiation occurs upon printing.
In the first embodiment, an energy level to be applied to the recording head for attaining a temperature increase is determined with reference to control data tables on the basis of an ambient temperature and a print time and a non-print time of the recording head before the present print operation is started, so that temperature control can be realized by open-loop control by using only an adjusted temperature sensor of a main body.
In a printer for mainly printing characters, since a print rate of a character itself is low, an average print rate is about several % to 30%. Therefore, a temperature can be sufficiently anticipated by open-loop temperature control on the basis of data anticipated by the main body according to operation control parameters such as a print time and a non-print time which can be easily measured by the printer like in the first embodiment, and a temperature control energy supply amount can be adjusted.
However, in a printer for mainly printing graphic data at high speed, since an average print rate is largely changed between several % to 100%, an over heat state tends to occur, as shown in Fig. 16, by only operation control parameters such as a print time and a non-print time when a temperature control energy and a heat generation energy caused by a discharge operation at a high print rate overlap each other. For this reason, irregular discharge problems such as a non-discharge state, splash, a fixing error caused by an excessive discharge amount, density nonuniformity, and the like are posed, and a graphic printer which is required to have high print quality becomes unsatisfactory.
In order to prevent an overhead state caused by a high print rate, a thermal equilibrated temperature may be set to be lower than that of a character printer under an assumption of a high average print rate. At this time, when a print pattern having a low print rate is to be printed, since a self temperature increase is small in the above-mentioned open-loop temperature control during printing, the actual temperature of the recording head is shifted to a lower temperature, and low density or density nonuniformity occurs. Thus, only an unsatisfactory print result is obtained by a high-speed graphic printer.
During a print operation of a graphic pattern having a high print rate, when a temperature at the end of the first page becomes very high, and in particular, when the print operation of the page is completed immediately before the temperature reaches an over heat temperature, a cooling operation requires more time than that at an assumed average print rate. For this reason, in the open-loop temperature control before printing, a temperature increase energy excessively larger than that required for the next print control before printing (without correction) is performed is the same as that shown in Fig. 10, and is omitted. Fig. 18 similarly shows a change in temperature of the recording head when both the temperature control operations before and during printing (without correction) are performed.
Fig. 19A shows a change in print rate, Fig. 19B shows a change in temperature of the recording head in correspondence with a change in print rate shown in Fig. 19A when the temperature control operations before and during printing according to the second embodiment of the present invention are performed, and Fig. 19C shows a change in operation amount of a temperature control energy.
A thermal equilibrated temperature shown in Figs. 17 and 18 is set to be higher than those shown in Figs. 11 and 12. The first embodiment takes self heating of the recording head into consideration when the thermal equilibrated temperature is set. In this embodiment, however, since a self heating portion is corrected in the temperature control during printing, the self heating portion need not be taken into consideration when the thermal equilibrated temperature is set.
For this reason, an energy supply amount of the temperature control during printing according to this embodiment is slightly larger than that in the first embodiment.
Temperature control according to the second embodiment of the present invention will be described below with reference to the flow chart shown in Fig. 20. Note that a change in temperature of the recording head by this temperature control corresponds to Fig. 19.
When the power switch is turned on, a wait time counter, a print time counter, a print pulse counter, a correction coefficient memory, and the like are reset to "0" (step S201) to initialize control parameters. The control then waits until a print signal is input (step S202).
When the print signal is input, an ambient temperature T obtained by the temperature sensor 8 on the printed circuit board 7 of the main body is read (step S203). An anticipated temperature T_FINI upon completion of the previous print operation (to be described in detail later) is then read (step S204). A wait time tw is then read from the wait time counter. At this time, the counter is reset to "0" as described above. The temperature control data tables before and during printing (Tables 3 and 4) are referred to on the basis of the wait time tw and the ambient temperature (step S205). At this time, since there is no temperature increase caused by the print operation and an ambient temperature is the same as the room temperature, output data as a determination value of the temperature control power Pp_reo table before printing becomes one of 0 to 100% according to the ambient temperature, and has a larger value than those obtained in correspondence with other wait times (step S206).
On the basis of this output data, a temperature control operation amount Pp_re before printing = P_preo x f(T_FINI) is calculated (step S207). The function f has a negative correlation with the anticipated temperature T_FINI upon completion of the previous print operation. The temperature control heater 10 shown in Fig. 7 is heated on the basis of the calculated operation amount Pp_re, and the temperatures of the nozzle portion 9 and the common ink chamber 12 of the recording head 2 are increased (step S208). In this embodiment, an energization time is prolonged as a temperature becomes lower. After completion of energization, a print start timing is waited for about 1 sec to disperse an abrupt temperature distribution formed in the recording head. At that time, the wait time counter is reset (step S209), and the print time counter is started (step S210).
Temperature control conditions of the initial operation amount P_LINEO during printing obtained in step S206 are then corrected according to the content of the print signal. The temperature control conditions are corrected according to the length of one sub-scanning line. Like in steps S114 and S115 (Fig. 15) in the first embodiment, a power correction coefficient L for multiplying a correction coefficient proportional to a ratio of an actual moving amount to the full width of the carriage is calculated (step S211).
Discharge pulses for one second (number of print dots) of the next print content to be printed are counted to calculate an average print rate (print duty) (step S212).
Power correction coefficients P, and P₂ are calculated on the basis of the average print rate for every second (step S213). In this case, the power correction coefficient P₁ is a low-response correction coefficient, and is based on an average of average print rates for every seconds during previous 100 seconds. The power correction coefficient P₂ is a high-response correction coefficient, and is based on an average of average print rates for every seconds during previous 10 seconds. These correction coefficients P₁ and P₂ can be obtained by referring to the data table (Table 5) on the basis of the average print rate.
A temperature control operation amount P_uNE during printing is calculated on the basis of the obtained data.
In this embodiment, P_LINE= P_{LINEO X} P₁ x P₂ x L (step S214).
As described above, P_LINEO represents the temperature control initial operation amount during printing, and the correction coefficient L is one based on the carriage moving amount. The correction coefficient is normalized to a range between 0 to 1 (0% to 100%). As can be apparent from the above equation, when
In the third embodiment, high-precision temperature control can be performed even when a position of a recording head is physically separated from a position of a temperature sensor for measuring an ambient temperature.
In the first embodiment of the present invention described previously, the temperature sensor for measuring an ambient temperature is arranged not on a recording head unit but on an apparatus main body on which the recording head unit is mounted, and an anticipated control method is adopted wherein a temperature of the recording head is anticipated on the basis of a thermal time constant determined based on a heat capacity of the recording head, a print time, and a non-print time to control a temperature control amount.
According to this method, since the recording head does not have a temperature sensor, cost of the recording head as an expendable supply can be greatly reduced, and this can provide a considerably large merit in, especially, a disposable cartridge in which the recording head and an ink tank are integrated.
In the first embodiment, however, since the position of the recording head is physically separated from the position of the temperature sensor for measuring an ambient temperature, a temperature detected by the temperature sensor cannot often indicate a correct temperature at the position of the recording head. When a power supply circuit is incorporated in the apparatus, a temperature in the machine is increased due to heat generated by the power supply circuit. In this case, an increase in temperature in the machine varies depending on positions in the machine. Since the temperature sensor and the recording head have quite different orders of thermal time constant, even if the ambient temperature sensor and the recording head have the same temperature in the machine, a small error occurs between the temperature at the position of the recording head and the ambient temperature of the ambient temperature sensor before a lapse of a given time after power-on although these temperatures are finally equal to each other after the lapse of the given time. For this reason, in the first embodiment, a temperature control parameter for anticipated control is often determined on the basis of the temperature data including an error. Even if the identical apparatus and the identical recording head are used, a print density of prints may often be varied.
Open-loop temperature control according to the third embodiment will be described below. In this control, a temperature control parameter determined by parameters such as an ambient temperature, a print time, a non-print time, and the like is corrected according to an energization time of the apparatus main body or components in the machine which generate heat, so that a local difference in temperature increase in the machine, or an error in an anticipated temperature of the recording head caused by a time difference due to a difference in thermal time constant are corrected, thus attaining precise temperature control.
Fig. 22 shows a temperature increase in the machine near the temperature sensor for measuring an ambient temperature, and an actual temperature of the recording head at that time. Fig. 22 exemplifies data when a heat generation portion is separated from the recording head unit, and the recording head unit does not suffer from a temperature increase in the machine.
Fig. 23 shows an ambient temperature near the temperature sensor for measuring the ambient temperature, and an actual temperature of the recording heat at that time. Fig. 23 exemplifies data when the recording head unit suffers from a temperature increase in the machine.
Note that basic data of a change in actual temperature of the recording head with respect to the ambient temperature and the target temperature obtained when only the temperature control before printing is performed in a state wherein there is no temperature increase in the machine near the recording head is the same as that shown in Fig. 10, basic data similarly obtained when only the temperature control during printing is performed is the same as that shown in Fig. 11, and basic data obtained when the temperature control operations before and during printing are performance is the same as that shown in Fig. 12. In addition, a change in temperature of the recording head obtained when only printing is performed without temperature control is the same as that shown in Fig. 13.
Table 6 shows a correction table of a temperature increase in the machine in correspondence with Fig. 22. Note that above Tables 3 and 2 are used as temperature control data tables before and during printing.
Alternatively, when a temperature keeping current is not corrected based on the correction table, a small temperature keeping current may be supplied to the recording head unit during an ON period of a power supply, so that the recording head unit can have substantially the same temperature increase as that of the ambient temperature sensor unit. In this case, a current which is determined in correspondence with a thermal time constant of temperature increase characteristics of the recording head depending on a time from power-on regardless of a software program is supplied to the recording head. This control is equivalent to temperature correction in correspondence with a power-ON time. It is difficult more or less to correct the temperature of the recording head to be quite the same as the temperature increase of the ambient temperature sensor since the temperature increase of the ambient temperature sensor is attained by complex factors such as convection of air, heat transmitted from the circuit board, heat generated by the recording head itself, and the like. However, this control is satisfactory to correct a temperature increase in the machine.
In the above embodiment, heat generation according to a power-ON time is taken into consideration. Furthermore, heat generation according to an energization time of a discharge control driver such as a transistor or IC for printing may be taken into consideration. In this case, a read value of a temperature detected by the sensor unit is corrected on the basis of a sum of correction data for a temperature increase in the machine according to an energization time of the power supply unit and correction data for a temperature increase in the machine according to an energization time of, e.g., a transistor for printing. According to this arrangement, correction can be more reliably performed.
Of printers which are operated by an AC power supply, when an AC plug is connected, a main power supply unit is energized to initialize a control unit, and the like, and an actual print operation is performed after a power switch (software power switch) is turned on to energize the respective units of the main body. In a printer of this type, if an energization time of the main power supply unit is referred to as a hardware power-on time and an energization time in which the respective units are energized by actually turning on the software power switch is referred to as a software power-on time, if these times cause different heat generation amounts, the hardware and software power-on times are independently measured, and a sum of correction values from the corresponding correction tables may be subtracted according to their lapses of time.
Fig. 26 is a view for explaining a temperature increase in the printer, and its correction operation. Tables 7 and 8 show temperature correction tables according to hardware and software power-on times. As can be seen from Fig. 26, correction temperatures shown in Tables 7 and 8 are set in correspondence with a temperature increase in the machine ( T of the sensor temperature), and temperature increase correction can be precisely performed. The software and hardware power on times are measured up to a maximum of 60 minutes, and when they exceed 60 minutes, values at 60 minutes are held.
Note that correction according to energization times of the transistors and motors may be performed in addition to the above-mentioned temperature increase correction.
When software is turned off or a print operation is completed, a temperature may be subtracted on the basis of the software power-ON time or a print time.
pulse interval correction table is referred to on the basis of the measured pulse interval, thereby obtaining a correction coefficient. A temperature control operation amount during printing is corrected on the basis of the obtained correction coefficient.
On the other hand, when it is determined in step S401 that the temperature control pulse is not output, it is determined in step S404 whether 1.2 seconds have passed after the previous output. If NO in step S404, the flow returns to step S401. In a normal printing operation, since the temperature control pulse has a maximum of 1.2-second interval, the flow returns to step S401.
However, when the next print signal is waited, 1.2 seconds have often passed. In this case, the flow advances to step S405. It is determined in step S405 whether a capping state is set. If YES in step S405, no operation is performed, and the flow is ended. However, if YES in step S405, capping (Fig. 28) is performed in this embodiment when six seconds have passed upon completion of printing although capping is performed by a known means. In this case, the six seconds have passed to prevent a decrease in throughput occurring when capping is performed upon completion of printing because capping and uncapping require much time.
If NO in step S405, a temperature control pulse H is automatically output in step S406 to maintain the head temperature to the same temperature as in a carriage stop state. Since capping is performed when six seconds have passed upon completion of printing, a maximum of five temperature control pulses H are output. The flow then advances to steps S402.
In this embodiment, the same correction as in carriage moving amount correction is performed by measuring the temperature control pulse interval. Since the temperature control pulses H are kept output to maintain the head temperature constant until capping is performed even upon completion of printing, temperature control having higher precision than that in a printing restart mode can be performed.
The fifth embodiment of the present invention will be described with reference to Figs. 30 to 33 and Tables 10 to 12.
This embodiment exemplifies an operation for protecting the recording head from an over heat state although the recording head itself generates heat.
In the second embodiment described above, the over heat which tends to occur at a high print rate is prevented by correcting a temperature control power in accordance with a print rate. For example, when a print rate is 50% or more, as shown in Table 5, the correction coefficient is set to be 0%, and temperature control is not performed.
However, when a high print rate exceeding 50% is continued for a long period of time, an over heat state occurs by heat generated by the recording head itself. As is apparent from Tables 1 to 4, in order to prevent over heat, temperature control is not performed. However, in this case, an over heat state occurs due to heat generated by the recording head itself.
In this embodiment, the self temperature increase in the recording head is anticipated on the basis of a print rate. When an over heat state is determined by the anticipated temperature increase and an ambient temperature, printing in both directions is changed to printing in one direction, thereby preventing over heat.

S601, the protect value is reset to "0" in step S602. When printing is not performed for a period of 120 seconds or more, the temperature of the recording head is assumed to be decreased near the ambient temperature, thereby releasing the protect mode.
In step S603, the number of printing dots for 15 seconds is counted. In step S604, an average low-response print duty for past 120 seconds (8 times) is calculated of the number of printing dots counted in step S603. In step S605, the sum data table (Table 10) is referred to on the basis of the low-response print duty to obtain a sum. This sum is compared with the MAX value and if the protect value does not exceed the MAX value, the sum is added to the protect value (steps S606 and S607).
In step S608, when the low-response print duty is smaller than the previous low-response print duty obtained in step S604, discharge is taken into consideration. That is, in step S609, the difference data table (Table 11) is referred to on the basis of the protect value to obtain a difference. In step S610, the difference is subtracted from the protect value. In this case, when the protect value is smaller than zero, it is set to be zero (steps S611 and S612).
A limit value is obtained with reference to the limit data table on the basis of the ambient temperature (step S613). If the protect value does not exceed this limit value, printing in both directions is set (steps S614 and S615). Therefore, this state is canceled in printing in one direction (to be described later).
If the protect value exceeds the limit value, over heat is determined. In step S616, printing in one direction is set. In this state, the print duty is set to 1/2 that in printing in both directions, over heat can be prevented. Furthermore, when the ambient temperature exceeds 30 C, the wait time is set so that a period of 1.2 seconds is inserted before printing (steps S617 and S618). The print duty is decreased to 1/3 that in printing in both directions. Even if the ambient temperature is high, the temperature of the recording head can be quickly decreased.
According to the fifth embodiment, as described above, the increase in temperature of the recording head is anticipated on the basis of the print rate, and over heat of the recording head is detected. When over heat of the recording head is determined, printing is changed from printing in both directions to printing in one direction to reduce a print speed. An energy applied to the recording head in unit time can be reduced to prevent over heat.
In addition, the equilibrated temperature corresponding to the print rate and a discharge amount caused by a decrease in print rate is taken into consideration, thereby anticipating a temperature increase in the recording head. Therefore, high-precision protection against a temperature increase can be achieved.
When the temperature increase state is canceled by temperature increase protection, the mode is restored to printing in both directions to increase a recording speed.
In this embodiment, over heat of the recording head is protected by changing the mode from printing in both directions to printing in one direction. However, any method may be employed if an energy applied to the recording head in unit time can be reduced. For example, a predetermined wait time may be provided prior to printing of the next line, and the pulse width of the discharge heater may be shortened.
In the first to fifth embodiments described above, print time data, wait time data, the energization time data, and the like are preferably stored or timer operations are preferably continued during the power-off state due to the following reason. When data is lost upon a power-off operation, the previous temperature of the recording head is unknown when the power switch is turned on again. As a result, proper temperature control cannot be performed.
The sixth embodiment of the present invention will be described with reference to the accompanying drawings.
Fig. 34 is a perspective view illustrating an ink-jet recording apparatus which can suitably employ a temperature control method of the present invention.
The ink-jet recording apparatus is of a serial scan type in which a head cartridge integrally including a recording head and an ink tank is mounted on a carriage moved along a recording medium P such as a paper sheet or a plastic thin sheet.
This ink-jet recording apparatus includes an ink tank 1 and a recording head 2.
The recording head 2 is an ink-jet recording head which discharges an ink by utilizing heat energy. The recording head 2 comprises an electrothermal conversion element array.
The ink-jet recording head 2 discharges an ink from a discharge port upon growth of bubbles by film boiling generated by heat energy applied by the electrothermal conversion element, thereby recording information.
The ink tank 1 and the recording head 2 are integrally arranged to constitute a disposable (exchangeable) head cartridge as a whole.
The head cartridge is mounted on a carriage 3, and the carriage 3 is reciprocated in directions indicated by a double-headed arrow A along guide rails 4 so as to move along the recording medium P.
Referring to Fig. 40, power transistors are selected so that each of the heat capacities of the discharge heater drive power transistor 18a and the temperature control driving power transistor 18b is set to be 1/2 the heat capacity of the recording head 2. Alternatively, a heat sink is coupled to each power transistor to set so that a temperature increase in each power transistor 18a or 18b is doubled from the temperature increase in the recording head 2.
The temperatures of the power transistors 18a and 18b are measured by temperature sensors 8, and temperature signals from the sensors 8 are converted into digital signals by A/D converters 16. The digital signals are multiplied with each other in the MPU 17, and the product is additionally multiplied with a correction coefficient, thereby uniquely determining the temperature of the recording head from the temperatures of the power transistors 18a and 18b.
An ambient temperature (room temperature) sensor may be arranged and combined with the two temperature sensors 8 attached to the power transistors 18a and 18b, thereby correcting the measuring temperatures.
When the measured temperatures of the two power transistors 18a and 18b are lower than a predetermined temperature, the temperature control heater 10 is turned on, and a short pulse which does not cause formation of bubbles of the ink is applied to it, thereby heating the recording head 2.
When the measured temperatures of the two power transistors 18a and 18b exceed the predetermined temperature, at least one of the temperature control heater 10 is turned off, and supply of a short pulse to the discharge heater 13 is stopped is performed to prevent over heat of the recording head 2.
Figs. 41 A and 41 B are partial sectional views of printed circuit boards 7 for performing temperature control according to the eighth embodiment of the present invention.
Referring to Fig. 41A, a discharge heater driving power transistor 18a and a temperature control heater driving power transistor 18b are in contact with one temperature sensor 9.
Referring to Fig. 41 B, a discharge heater driving power transistor 18a and a temperature control heater driving power transistor 18b are in contact with a heat sink 28. In addition, a temperature sensor 8 is thermally coupled to the heat sink 28.
The temperature control method of this embodiment can be practiced using the same arrangement as the control system shown in Fig. 40.
In the arrangement of Fig. 41A, a total heat capacity of the two power transistors 18a and 18b is set to be equal to that of the recording head 2, or an analog signal from the temperature sensor 8 is converted into a digital signal by an A/D converter, and the digital signal is subjected to correction processing in an MPU 17. Therefore, the temperature of the recording head 2 can be uniquely determined from the temperatures measured by the temperature sensor 8. When the measured temperature is the predetermined temperature or less, at least one of the temperature control heater 10 and the discharge heater 13 is used to heat the recording head 2. When the measured temperature exceeds the predetermined temperature, heating of the recording head by at least one of the temperature control heater 10 and the discharge heater 13 is stopped, thereby performing temperature control of the recording head 2.
In the arrangement of Fig. 41 B, a total heat capacity of the two power transistors 18a and 18b and the heat sink 28 is selected to be equal to that of the recording head 2. Alternatively, the analog signals from the temperature sensor 8 are converted into digital signals by the A/D converters 16, and the digital signals are subjected to correction processing in the MPU 17. Therefore, the temperature of the recording head 2 is uniquely determined in accordance with the temperatures measured by the temperature sensor 8. In the same manner as described above, when the measure temperatures are the predetermined temperature or less, the recording head 2 is heated by at least one of the temperature control heater 10 and the discharge heater 13. However, when the measured temperatures exceed the predetermined temperature, heating of the recording head 2 by at least one of the temperature control heater 10 and the discharge heater 13 is stopped, thereby controlling the temperature of the recording head 2.
Fig. 42 is a partial sectional view of a printed circuit board for performing temperature control according to the ninth embodiment of the present invention. Fig. 43 is a block diagram of a control system suitably performing the temperature control of this embodiment.
Referring to Fig. 42, a temperature sensor 8 is located near a discharge heater driving power transistor 18a. In this case, in order to cause the temperature sensor 8 to effectively sense radiation heat or convection heat from the discharge heater driving power transistor 18a, the temperature sensor 8 is preferably located at a level higher than a heating source of the discharge heater driving power transistor 18a since heat is accumulated in the upper portion.
Referring to Fig. 43, in the control system of this embodiment, radiation heat and reflection heat from the power transistor 18a for the discharge heater 13 are measured by the temperature sensor 8, and an analog signal from the temperature sensor 8 is converted into a digital signal by the A/D converter 16. constituting components of the recording apparatus of the present invention to further enhance stability of the effect'of the present invention. Examples are a recording head capping means, a recording head cleaning means, a recording head pressing means, a recording head suction means, an electrothermal conversion element, another heating element, a combination of the electrothermal conversion element and this heating element, and an arrangement for setting a preliminary discharge mode for discharging independently of recording so as to perform stable recording.
A recording mode of the recording apparatus is not limited to a recording mode for only a major color such as black. An integral full-color recording head or a plurality of single-color recording heads may be used. The present invention is also effective to an apparatus having at least one of a plurality of different colors or a color mixing full-color mode.
In each embodiment described above, a liquid ink is used. However, an ink which is solidified at room temperature or less, an ink which is softened or melted even at room temperature, or the like may be used. Alternatively, an ink which is solidified or melted in the general temperature control range of 30 C to 70 C may be used in ink-jet printing. That is, any ink may be used when it is melted when a print signal is applied to the recording head. A temperature increase by a heat energy may be positively prevented by using a phase transition from the solid phase to the liquid phase, or an ink which is solidified in an exposed state to aim at prevention of evaporation of the ink may be used. In either case, an ink which is melted upon reception of the print signal of the heat energy may be used. In this case, the melted ink is discharged. In addition, an ink which is solidified at the time of its arrival on the recording medium, or an ink which is melted upon reception of heat energy may be applied to the present invention. In this case, as described in Japanese Laid-Open Patent Application No. 54-56847 or 60-71260, an ink may oppose the corresponding electrothermal conversion element while the ink is held in a recess portion of a porous sheet or held as a liquid or solid body in a through hole. According to the present invention, a film boiling scheme is most effective for these inks.
In addition, as the form of an ink-jet recording apparatus, the apparatus may be used as an image output terminal for a data processing unit such as a computer, a copying machine as a combination with a reader or the like, and a facsimile apparatus having a transmission/reception function.
According to the present invention, as has been described above, correction associated with the temperature of the control circuit area is performed for a control object member (the ink-jet recording apparatus recording means in each embodiment) to eliminate a control error as in a technique for detecting the state of the recording means while a direct temperature measurement is performed. Since detection or anticipation precision is better than temperature control by the conventional temperature sensor and the detection error range of the temperature sensor itself, execution modes based on various temperatures can be accurately performed.
In addition to the ink-jet recoding head utilizing a heat energy, the present invention is applicable to heating elements driven individually or in units of predetermined groups, such as a thermal head for applying a heat energy to an ink ribbon or a porous ink convey unit. In this case, any temperature sensor need not be arranged directly on or near the heating element. Disconnections of the sensor and sensor wiring lines can be eliminated, and the measurement is free from sensor variations. In particular, in a recording heating element array, each heating portion is locally heated to slightly change the response of the temperature sensor, thereby disabling accurate determination. The present invention can solve this.
In particular, the present invention provides marvelous effects in a control object member (e.g., an ink-jet recording head using an ink (solid or liquid)) having various thermal parameters such as an ink heat capacity, a head structure, and heating of the above member. These parameters cause variations in position for accurately determining the temperature due to a use or drive state. Therefore, it is difficult to determine a timing at which accurate determination is performed. However, the present invention can solve this drawback.
In a bubble-jet machine utilizing an ink-jet boiling film, proposed by CANNON INC., the film temperature locally exceeds 300 ° C due to heat-insulating expansion of bubbles. Even if the parameters having large variations are included, or a local heating portion such as a driving switching diode is included, variation factors can be systematically determined to perform temperature control, thus proving superiority of the present invention over the prior arts.
In the scanning type recording apparatus for scanning a recording head to perform recording, an operation error of the temperature detection sensor occurs due to a scanning speed and a difference between speeds during scanning and the stop state. The present invention can solve this problem.
In the embodiments described above, technical arrangements based on the description of the respective components, and their modifications may be incorporated in the present invention in a combination without departing the spirit and scope of the invention. the basis of the energization time, controls the energy supplied to said heat means during the recording operation on the basis of the corrected ambient temperature and the record time, and controls the energy supplied to said heat means prior to the recording operation on the basis of the corrected ambient temperature and the non-record time.
15. An apparatus according to claim 13, wherein

said energization time measurement means measures a first energization time for energizing a power source unit in said apparatus and a second energization time for energizing each component in said apparatus, and
said control means controls the energy supplied to said heat means on the basis of the first and second energization times.

16. An apparatus according to claim 8, wherein said recording head has a plurality of discharge ports for discharging the ink with the heat energy.
17. An apparatus according to claim 8, wherein said recording head comprises a plurality of discharge ports for discharging an ink, and heat energy generation means, arranged in units of discharge ports, for causing a state change in ink by heat, discharging the ink from said discharge port on the basis of the state change, and forming a flying droplet.
18. An apparatus according to claim 8, wherein said recording head is of a disposable type detachably formed in said apparatus.
19. An apparatus according to claim 8, wherein said recording head is of a full-line type having a plurality of discharge ports extending in an entire recording width of a recording medium.
20. An apparatus according to claim 8, wherein said apparatus is applied to a facsimile apparatus for recording a recording signal received through a communication line.
21. An apparatus according to claim 8, wherein said control means controls the supply energy on the basis of a pulse width of a drive pulse supplied to said heat means.
22. An apparatus according to claim 1, further comprising:

print rate measurement means for measuring a print rate in a predetermined time of said recording head; temperature increase anticipating means for anticipating a temperature increase caused by a recording operation of said recording head itself on the basis of the print rate measured by said print rate measurement means; and
temperature increase protection means for limiting supply of the recording energy to said recoding head on the basis of the temperature increase anticipated by said temperature increase anticipating means.

23. An apparatus according to claim 22, wherein said temperature increase protection means limits supply of the recording energy by changing recording in both directions to recording in one direction.
24. An ink-jet recording apparatus for discharging an ink droplet from a recording head to perform recording, comprising:

heat means for heating said recording head;
temperature measurement means for measuring an ambient temperature;
print rate measurement means for measuring a print rate during a predetermined time of said recording head; and
control means for controlling an energy to be supplied to said heat means on the basis of the ambient temperature measured by said temperature measurement means and the print rate measured by said print rate measurement means.

25. An apparatus according to claim 24, wherein said print rate measurement means measures the print rate by counting the number of ink discharge pulses per unit time.
26. An apparatus according to claim 24, wherein

said print rate measurement means measures print rates of a first period and a second period longer than the first period, and
said control means controls the energy supplied to said heat means on the basis of the print rates of the first and second periods.

27. An apparatus according to claim 24, further comprising:

timer means for measuring a record time of said recording head, and wherein
said control means controls the energy supplied to said heat means on the basis of the record time measured by said timer means.

28. An apparatus according to claim 24, further comprising:

timer means for measuring a non-record time of said recording head; and wherein
said control means controls the energy supplied to said heat means on the basis of the non-record time measured by said timer means.

29. An apparatus according to claim 24, wherein said recording head has a plurality of discharge ports for
48. An apparatus according to claim 42, wherein said apparatus is applied to a facsimile apparatus for recording a recording signal received through a communication line.
49. An apparatus according to claim 42, wherein said control means controls the supply energy on the basis of a pulse width of a drive pulse supplied to said heat means.
50. An ink-jet recording apparatus for discharging an ink droplet from a recording head to perform recording, comprising: heat means for heating said recording head; an electronic element for supplying an energy to said recording head; temperature measurement means for measuring a temperature of said electronic element; and control means for anticipating a temperature of said recording head on the basis of a temperature of said electronic element measured by said temperature measurement means.
51. An apparatus according to claim 50, wherein said control means controls the energy supplied to said heat means on the basis of the anticipated temperature of said recording head.
52. An apparatus according to claim 51, wherein said temperature measurement means is formed on a printed circuit board in said apparatus.
53. An apparatus according to claim 52, wherein said temperature measurement means is in contact with said electronic element.
54. An apparatus according to claim 50, wherein said recording head has a plurality of discharge ports for discharging the ink with the heat energy.
55. An apparatus according to claim 50, wherein said recording head comprises a plurality of discharge ports for discharging an ink, and heat energy generation means, arranged in units of discharge ports, for causing a state change in ink by heat, discharging the ink from said discharge port on the basis of the state change, and forming a flying droplet.
56. An apparatus according to claim 50, wherein said recording head is of a disposable type detachably formed in said apparatus.
57. An apparatus according to claim 50, wherein said recording head is of a full-line type having a plurality of discharge ports extending in an entire recording width of a recording medium.
58. An apparatus according to claim 50, wherein said apparatus is applied to a facsimile apparatus for recording a recording signal received through a communication line.
59. An apparatus according to claim 50, wherein said control means controls the supply energy on the basis of a pulse width of a drive pulse supplied to said heat means.
60. A method of controlling a temperature of an ink-jet recording apparatus having a recording head for discharging an ink droplet, heat means for heating said recording head, temperature measurement means for measuring an ambient temperature, and timer means for measuring a non-record time of said recording head, comprising: the first step of, just before a recording operation, supplying an energy to said heat means to control a temperature of said recording head on the basis of the ambient temperature measured by said temperature measurement means and the non-record time measured by said timer means; and the second step of supplying a recording signal to laid recording head to perform recording.
61. A method according to claim 60, wherein the first step comprises increasing the energy supplied to said heat means when the non-record time is long.
62. A method according to claim 60, wherein the first step further comprises controlling the temperature of said recording head by supplying the energy to said heat means on the basis of a print rate in a predetermined time of said recording head.
63. A method according to claim 62, wherein the first step comprises decreasing the energy supplied to said heat means when the print rate is high.
64. A method according to claim 60, wherein the first step further comprises controlling a temperature of said recording head by supplying the energy to said heat means on the basis of an energization time of said apparatus.
65. A method of controlling a temperature of an ink-jet recording apparatus having a recording head for discharging an ink droplet, heat means for heating said recording head, temperature measurement means for measuring an ambient temperature, and timer means for measuring a record time of said recording head, comprising: the first step of, during a recording operation, supplying an energy to said heat means to control a temperature of said recording head on the basis of the ambient temperature measured by said temperature measurement means and the record time measured by said timer means; and the second step of supplying a recording signal to said recording head to perform recording.
66. A method according to claim 65, wherein the first step comprises decreasing supply of the energy to

Claims

1.