JPH04250057A - Ink jet recording device - Google Patents

Abstract

PURPOSE:To provide an ink jet recording device which is capable of reducing the occurrence of unevenness in an ink discharge amount not by temperature distribution occurring according to a discharge port used for recording. CONSTITUTION:By changing drive control, e.g. control of temperature adjustment and control of a drive pulse, in a plurality spots, e.g. right and left, according to a discharge port, e.g. the number of discharge ports and the position of the discharge port, used for recording, the occurrence of unevenness in a discharge amount can be reduced but not by temperature distribution of a head. Thereby, the occurrence of unevenness in concentration and production of a joint rib are prevented, and concentration and a color balance during printing of a final line and reduction printing can be stabilized.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating type ink jet recording apparatus that utilizes ink ejection amount control.

0002

[Prior Art] Conventionally, in inkjet recording devices that use thermal energy generated by an ejection heater, in order to eliminate density fluctuations and density unevenness among ink ejection performance, ejection speed and direction (landing accuracy) ) and discharge amount VDR
The aim was to stabilize the ejection characteristics regarding OP [pl/dot]. In order to stabilize this, the following method was used.

1. Continuous head temperature control (external/internal) feedback available.

2. Sequential head temperature control (external/internal) with feedback.

3. High temperature head temperature control (higher temperature than ambient temperature)
With feedback.

However, 1.2.3. With this method, density fluctuations and density unevenness could not be completely eliminated due to ink evaporation, changes in head structure, and lack of control accuracy due to temperature control ripples.

Accordingly, a divided pulse width modulation driving method has been proposed as a method for supplying driving pulses to the ejection heater. This is a driving method in which a preheat pulse with a variable pulse width is first applied, and then a main heat pulse is applied at an interval time. The preheat pulse is a pulse mainly used to control the ink temperature within the nozzle, and the pulse width is varied by temperature detection using a temperature sensor of the head. At this time, the pre-foaming phenomenon is prevented by applying too much thermal energy to the H/B. The interval time is a constant time interval so that the preheat pulse and the main heat pulse do not interfere with each other, and has the function of making the temperature distribution of the ink in the nozzle uniform. The main heat pulse causes a bubbling phenomenon to occur on the H/B and causes ink droplets to be ejected from the nozzle holes.

By using this divided pulse width modulation driving method, it is possible to eliminate density fluctuations and density unevenness due to fluctuations in ejection amount during printing.

However, printing is not always performed using all the nozzles; for example, it is conceivable that printing is performed using only one half of the nozzles. In other words, the relationship between the printing area and the printing width of the head is not necessarily a positive multiple of the printing width, and the last line of printing must be printed with odd nozzles.

[0010] Furthermore, when using an inkjet recording device using a control signal from an external device such as a reading device,
There are cases where it is necessary to change the number of nozzles in the head from the normal printing state. For example, in an inkjet recording device using a serial printing method, the paper feed accuracy is normally determined by the feed (head width).
Since it is designed to be stable at 300 degrees, changing the paper feed during reduction will reduce accuracy and cause stitches, which will disrupt the image. For this reason, two-pass printing, in which printing is performed twice for one paper feed, is effective. In such a case, it is necessary to print by changing the number of ejection nozzles of the head.

As described above, when the number of printing nozzles in the head is changed, a temperature distribution occurs depending on the usage status of the discharge heater, and the discharge amount varies depending on this temperature distribution. Furthermore, in an inkjet recording apparatus in which head drive is controlled by a temperature sensor, if control is not performed in consideration of temperature distribution, uneven print density will occur as a result.

[0012] When color printing is performed using the four colors cyan, magenta, yellow, and black under the above conditions,
Since the color balance of the full-color image that is formed is disrupted, the image quality deteriorates due to changes in color tone and decreased color reproducibility (increased color difference). Also, black, red, blue,
When a monochromatic image such as green is formed, there are problems such as density unevenness.

The present invention has been made to solve the above-mentioned problems, and is an inkjet recording method that can reduce variations in ink ejection amount without depending on the temperature distribution that occurs depending on the ejection ports used for printing. The purpose is to provide equipment.

[0014]

Means for Solving the Problems In order to achieve the above object, an inkjet recording apparatus of the present invention uses an inkjet recording head equipped with a plurality of ejection heaters and a temperature sensor corresponding to the ink ejection openings, The inkjet recording apparatus determines the driving conditions for the recording head based on the detected temperature, characterized in that the driving conditions for the recording head are changed depending on the ejection ports used for recording.

[0015]

[Operation] According to the present invention, head drive control (e.g., temperature control control, drive pulse control) can be performed at multiple locations (e.g., temperature control control, drive pulse control) depending on the ejection ports used for recording (e.g., depending on the number and position of ejection ports). For example, by changing the discharge amount (left and right), it is possible to reduce variations in ejection amount regardless of the temperature distribution of the head, eliminating density unevenness and connecting lines, and improving the density and color balance during final line printing and reduced printing. Stabilization becomes possible.

[0016]

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

FIGS. 1 to 3 are flowcharts showing main control of an inkjet recording apparatus according to an embodiment of the present invention, and an outline of the main control will be explained using FIGS. 1 to 3.

When the power is turned on, the device performs an initial check in step S1. This check is to check the ROM and RAM of this device, that is, to check the programs and data to confirm whether the device can operate normally. In step S2, the correction value of the temperature sensor circuit is read. In step S3, an initial jam check is performed. In this embodiment, an initial jam check is performed in step S3 even when the front door is closed. In step S4,
In the next step, necessary checks are performed on the apparatus side when reading the information of the recording head. In step S5, data in the ROM built into the recording head is read. Next, in step S6, initial data is set.

In step S7, initial temperature control of 20° C. is started, and in step S8, recovery operation determination [1] (determination as to whether or not a suction recovery operation is to be performed when the power is turned on) is performed. The above is an explanation of the sequence flow up to the wait state.

Next, the sequence flow in the standby state will be explained. In step S9, temperature control is performed at 20° C., and in step S10, standby empty discharge is performed. In step S11, it is checked whether there is no paper feeding. If no paper is being fed, the process advances to step S21. It is checked in step S12 whether the cleaning button has been pressed, and if it has been pressed, a cleaning operation is performed in step S13. If the RHS button is pressed in step S14, an RHS mode flag is set in step S15. Here, RHS refers to a head shading process for correcting density unevenness of a recording head, and the density unevenness of a printed pattern is read by a reading section (reader) and the density unevenness is corrected.

If paper is manually fed in step S16, a manual feed flag is set in step S17, and the process advances to step S22, which is a copy start sequence. If the OHP button is turned on in step S18, step S19
The OHP mode flag is set in step S20, and if it is not turned on, the OHP mode flag is reset in step S20. If the copy button is pressed in step S21, the process advances to step S22, which is a copy start sequence. on the other hand,
If it has not been pressed, the process returns to step S9. Step S1
Step S9 is also performed when the cleaning operation is completed in step S9.
Return to

Next, the copy sequence will be explained. In step S22, a fan is rotated to suppress the temperature rise inside the machine, and in step S23, temperature control is started at 25°C. Step S
Check whether there is no paper feeding in step S24, and if there is no paper feeding, step S25
Perform idle discharge [1] (N=100) in step S29.
Proceed to. Here, N indicates the number of times of dry ejection. Step S
In step S26, a recovery operation determination [2] (determination as to whether or not to perform a suction recovery operation before paper feeding) is made, and in the next step S27, paper is fed. In step S28, paper width and paper type detection operations are performed. In step S29, it is determined whether the image should be moved. If the image is to be moved, sub-scanning movement (paper movement) is performed in step S30, and if the image is not to be moved, the process advances to step S31. In step S31, it is checked whether the temperature of the write head is 25° C. or higher. If the temperature is 25℃ or higher, proceed to step S.
In step S32, a recovery operation determination [3] (determination as to whether or not to perform a recovery operation based on the amount of ink evaporation in the non-capping state) is performed, and in step S33, a recording operation for one line is performed. Thereafter, a recovery operation determination [6] (determination as to whether or not to perform a recovery operation based on the wiping timing) is performed in step S34, and the paper is transported in step S35.

[0023] In step S36, it is checked whether the recording operation has been completed. If the process has been completed, data such as the number of printed sheets is written into the ROM of the head, and then the process advances to step S37. If the process has not ended, the process returns to step S31. In step S37, it is checked whether or not to move to standby state, and if it is to move to standby state, the process advances to step S38.

Step S38 and subsequent steps are a routine for performing paper ejection operation and recovery operation judgment [4] after printing one sheet (removal of printing bubbles, removal of air bubbles in the liquid chamber, cooling at abnormally high temperature, and recovery). In step S38, it is checked whether or not there is a paper ejection operation. If there is no paper ejection operation, wait for the temperature to drop below 45° C. in steps S39, S40, and S41, and if the temperature does not drop within 2 minutes, stop the abnormality in step S42. If the temperature is below 45°C, a wiping operation is performed in step S50, and step S
At step 43, perform a dry discharge operation (N=50), and then proceed to the next step S4.
Capping with 8. If there is a paper ejection operation, step S
At step 44, the sheet is ejected. Check whether continuous printing is performed in step S45, and if it is continuous printing, determine recovery operation in step S47 [4]
After that, the process returns to step S24. If it is not continuous printing,
A recovery operation determination [4] is performed in step S46, and after the determination, capping is performed in step S48 as in the case of no paper discharge. Then, in step S49, the fan is stopped, the process returns to step S9, and the copying operation ends.

FIG. 4 is a flowchart showing details of the initial jam check routine in step S3. This routine detects a jam immediately after the power is turned on. Step S
From step S201 to step S204, it is checked whether there is recording paper or the like in the conveyance path or near the carriage using a paper feed sensor, a paper discharge sensor, a paper floating detection sensor, and a paper width sensor, respectively. If there is, it is determined that there is a jam and a warning is issued; if not, the process returns to the main flow. FIG. 5 is a flowchart showing details of the head information reading routine in step S5. In step S301, the serial number unique to the write head is read, and it is determined whether the value of the serial number is FFFFH (step S302). If the serial number is FFFFH, it is determined in step S304 that there is no head, and an error occurs. If the serial number is not FFFFH, the color information of the head is read in step S303. Step S
In step 305, it is checked from the color information whether the head is installed in the correct position designated for each color. If it is installed correctly, the process advances to step S306; if it is incorrectly installed, the process advances to step S307.

In step S306, the remaining head information (
Print pulse width, temperature sensor correction value, number of prints, number of wiping, etc.) are read and stored. In step S308, it is determined whether the installed write head is new.
Check by comparing the serial numbers of the heads. The serial number of the head is always stored in the backup RAM and can be compared with the data read from the head. If the two values are different, a new head will be installed,
If the values are equal, it can be determined that the head has not been replaced. In this embodiment, this is performed for each of the colors Bk, C, M, and Y. If the head is not a new head, the head information reading routine ends. If the head is a new head, the new head information is stored in the memory within the apparatus in step S309, and a flag (or data) indicating that the new head is installed is set in the memory. Next, step S
In step S310, the HS data (shading information) of the write head is read, and in step S311, the time when this new head starts to be used is written from the clock in the device to the nonvolatile memory in the head, and the head information reading routine is ended.

The method of using the head ROM will now be explained in detail. (Drive Settings) The device used in this embodiment uses a replaceable head (cartridge type) and has the advantage that the user can replace the head at any time. Therefore, detailed adjustments of the device by a service person or the like cannot be expected. In addition, since these replaceable heads are supplied through mass production, each head may have different characteristics due to variations in the manufacturing process such as the area, resistance value, and film structure of the heater board (H/B) mentioned above. have. Therefore, in order to more stably obtain high image quality, it is necessary to correct the above-mentioned variations in characteristics.

As a method of correcting such differences in drive condition settings for each head, correction is performed by reading ROM information, and density unevenness due to variation in ejection amount within one head due to the distribution of the ejection hole diameter of the head is corrected. method (reading H/S data).

[0029] If such correction is not performed for each head, the ejection characteristics, especially the ejection speed and direction (landing accuracy)
, ejection amount (density), ejection stability (refill frequency, unevenness, wetting), etc. are not optimized. For this reason, not only is it not possible to obtain a stable image, but also significant image disturbance occurs due to non-discharge or deviation that occurs during printing.

Furthermore, since a full-color image in particular is formed by four heads: cyan, magenta, yellow, and black, if even one color is printed with a head that has a different ejection amount or control characteristics than the standard state, the image will not be printed. cause trouble. Among these, variations in discharge amount disrupt the overall color balance, resulting in changes in color tone and decreased color reproducibility (increased color difference).
This will reduce the image quality. black, red, blue,
In a monochromatic image such as green, density fluctuations occur. Further, variations in control characteristics change halftone reproducibility. Therefore, in this embodiment, these variations in ejection characteristics are corrected.

First, the printing method in this embodiment will be explained in detail. (Printing method) In this embodiment, features are given to the head driving method and the printing method. A split pulse width modulation (PWM) driving method is used to drive the head. As shown in Figure 6, Vop is the electrical energy that provides the electrical energy necessary to generate thermal energy on the H/B, and depends on the area, resistance value, film structure, etc. of the H/B. Determined by the nozzle structure of the head. P1 indicates the preheat pulse width, P2 indicates the interval time, and P3 indicates the main heat pulse width. T1, T2, and T3 are times from the rise of the preheat pulse, and indicate the times for determining P1, P2, and P3, respectively.

The divided pulse width modulation driving method uses P1, P2
, P3. P1 is a preheat pulse and has a pulse width mainly for controlling the ink temperature in the nozzle, and the pulse width of P1 is controlled by temperature detection using a temperature sensor of the head. At this time H.B.
Pre-foaming phenomenon is avoided by applying too much thermal energy to the top.

P2 is an interval time, and serves to provide a constant time interval so that the preheat pulse P1 and the main heat pulse P2 do not interfere with each other, and to make the temperature distribution of the ink in the nozzle uniform. P3 is a main heat pulse that causes a bubbling phenomenon to occur on the H and B and causes ink droplets to be ejected from the nozzle holes. These pulse widths are H
- Determined by the area of B, resistance value, film structure, head nozzle structure, and ink physical properties.

In this embodiment, a head having a head structure as shown in FIG. 7 is used. Head temperature TH = 25
．． In an environment of 0 (℃), Vop = 18. When 0 (V), P1 = 1. 867 (μsec), P3 =
4. When a pulse of 114 (μsec) is applied, the driving conditions are optimal and a stable ink ejection state can be obtained. The ejection characteristics at this time are the ink ejection amount Vd = 30. 0
ng/dot, discharge speed V=12. 0m/se
It was c. By the way, the highest driving frequency of the head is fr
= 4.0 KHz, has a resolution of 400 dpi, and divides 128 nozzles into 16 blocks to create 1 block.
It is driven sequentially from k. The head in this embodiment has a ROM in which characteristics of each head are recorded, and by reading this information into the main body, variations in characteristics of each head can be corrected.

A method for correcting this variation in ejection characteristics between heads and performing optimal image formation will be described below. When the power is turned on to the main unit equipped with a head, the head's RO
The information (ROM information) stored in M at the time of manufacturing the head is read into the main body side. At this time, head ID number, color information,
TA1 (head drive condition table corresponding to print pulse width)
(PWM table pointer), TA3 (PWM table pointer),
Reads information such as temperature sensor correction value, number of prints, and number of wiping. Table pointer TA read here
1, on the main body side, the value of the main heat pulse width: P3 of the divided pulse width modulation drive control method, which will be described later, is determined.

FIG. 8 shows table pointers: TA1 and TA1.
The main heat pulse width obtained from P3 is shown below.

(1) Determination of TA1: When manufacturing the head, the ejection characteristics of each head were measured in advance under standard driving conditions (head temperature: TH = 25.0 (°C)) and the driving voltage:
P1 = 1.87 when Vop = 18.0 (V)
(μsec) P3 = 4.114 (μsec)
The optimum driving conditions for each head are determined and stored as information in the ROM of the head.

(2) Driving condition setting: On the main body side, each pulse width during divided pulse width driving Preheat pulse width: P1
, interval time width: P2, and main heat pulse width: P3, the time from the rise of the preheat pulse is set as T1 and T2 as shown in FIG.
, T3 and T3 (T3 = 8.602 μs
ec ) value is fixed on the main unit from the beginning. Pulse width condition T2 given by the pointer read from the head: TA1 (for example, TA1=4.488 μse
P3 (P3 = T3 - T2 =
4.114 μsec).

As described above, by reading the head drive condition setting table pointer TA1 stored in the ROM of the head as information and changing the setting conditions (drive conditions) on the main body side, variations in ejection characteristics for each head can be reduced. This makes it possible to easily stabilize color image quality even when using replaceable heads.

(Correction method using PWM) Here, in order to more effectively utilize the PWM control method used in this embodiment, which is a method for correcting the dispersion of ejection amount among heads and performing optimal image formation. We will describe the method.

The PWM control conditions are such that when the power is turned on to the main body to which the head is attached, the ROM of the head is
Information is read along with ID number, color, driving conditions, and HS data. In this embodiment, table pointer: TA3 is read as a PWM control condition. As will be described later, this number TA3 is assigned a number corresponding to the ejection volume (VDM) of the head, and according to the read TA3, the main body side determines the upper limit of the PWM preheat pulse width: P1.

Next, the correction method using PWM will be explained in order.

(1) Determination of table pointer TA3: During head manufacturing, the ejection amount of each head is measured in advance under standard driving conditions (head temperature: TH=25.0 (°C)). Voltage: When Vop = 18.0 (V), P1 = 1.87 (μsec) and P3 = 4.1
14 (μsec) pulse application), and the value is taken as the measured discharge: VDM. Next, standard discharge amount: VD
0=30.0 (ng/dot) △V=VD0-
Obtain as VDM.

From this ΔV, the relationship between the value of ΔV and the table pointer: TA3 was determined as shown in FIG. In this way, the inks are ranked according to the ejection amount, and the TA3 for each head is stored as information in each ROM.

When creating a table from △V, it is necessary to make the change in one table of preheat pulse width P1, which can be controlled by the divided pulse width modulation driving method described later, equal to △VP. be. That is, this is because the ejection amount of the head is corrected by the preheat pulse width P1, as will be described later.

(2) Reading the table pointer: As shown in (1) above, the head with the information stored in the ROM of the head is attached to the main body of the inkjet printing apparatus, and when the power is turned on, the table pointer is read. According to the sequence shown in 5, the information stored in the head ROM is transferred to the SRAM on the main body side.
to be memorized.

(3) PWM control table determination: 1. For heads with a large discharge amount, the value of the preheat pulse width P1 at 25.0°C is set to the standard driving condition (P1 = 1.867
μsec) to reduce the ejection amount and bring it closer to the standard ejection amount VD0. 2. For heads with a small discharge amount, the value of the preheat pulse width P1 at 25.0°C is set to the standard driving condition (P1 = 1
．． 867 μsec) to increase the ejection amount and bring it closer to the standard ejection amount VD0. 3. As shown in FIG. 9, in the above operation, the relationship between the table pointer TA3 and the preheat pulse width P1 is determined according to the ejection amount of each head, so that the standard ejection amount VD0 is always maintained. It has been set. 4. By such a method, the standard discharge amount VD0 ( 3
0.0ng/dot) to ±0.6(ng/dot)
) It is now possible to correct variations in the discharge amount. As described above, the PWM control table pointer TA3 is read as head ROM information, and the setting conditions (
By changing the drive conditions (driving conditions), it became possible to absorb variations in ejection amount from head to head, and it became possible to easily stabilize color image quality even with a main body using replaceable heads. Furthermore, since the yield of heads can be improved, it has also become possible to reduce the cost of cartridge heads.

Next, the ejection amount control method using the preheat pulse: P1 will be described in detail. Head temperature (T
H) FIG. 10 shows the relationship between the preheat pulse width: P1 and the discharge amount: Vd under certain conditions. As shown in the figure, as the preheat pulse width P1 increases, P
It increases linearly up to 1LMT, and after that, the foaming of main heat pulse P3 is disturbed by the pre-foaming phenomenon, and P
After 1 MAX, the discharge amount tends to decrease.

Under the constant condition of preheat pulse width: P1, the relationship between head temperature: TH (environmental temperature) and discharge amount: VD increases linearly as the head temperature TH increases, as shown in FIG. shows a tendency to The coefficient of each region showing linearity is the preheat pulse dependence coefficient of discharge amount: KP = △VDP/ △P1 (ng/μs・dot
) Head temperature dependence coefficient of discharge amount: KTH=△VDT/△TH (ng/℃・dot)
It is determined as follows.

In the head structure shown in FIG. 61, KP
=3.21 (ng/ μsec ・dot), KTH=
It was 0.3 (ng/μsec·dot). If these two relationships are effectively used as explained below, the ink ejection amount of the head can be kept constant even if the head temperature changes due to various factors such as fluctuations in environmental temperature or fluctuations due to self-heating due to printing. This makes it possible to control the discharge amount by keeping the amount constant. FIG. 12 shows how the ejection amount is controlled with respect to the head temperature in terms of the relationship between the head temperature and the ejection amount. In FIG. 12, T0 indicates the standard temperature, TL indicates the limit temperature for discharge rate control, and TC indicates the foaming limit temperature.

Discharge amount control is performed under the following three conditions. (1) TH≦T0 Compensation for the discharge amount at low temperatures is performed by controlling the head temperature. (2) T0 <TH ≦TL Discharge amount control is performed using divided pulse width modulation (PWM). (3) TL < TH (< TC ) P1 = constant and non-controlled.

The state (1) is intended to ensure the discharge amount mainly in a low temperature environment in the temperature control region of FIG. 12. When head temperature TH = 25.0℃ or less, head temperature TH
The temperature control temperature T0 = 25. By keeping it constant at 0 (°C), the discharge amount when TH = T0 is VD0 = 30. 0
(ng/dot). T0 is 25. The reason for setting the temperature to 0° C. is to eliminate as much as possible adverse effects such as ink thickening, ink sticking, and temperature control ripples due to temperature control. The pulse width of P1 at this time is P1 = 1. 867 μs
It is ec.

The state (2) is the PWM region shown in FIG. 12, where the head temperature TH is 26. 0℃~44. 0
It is carried out between ℃. A sensor detects temperature rise due to printing and changes in environmental temperature. The preheat pulse width P1 is determined by the head temperature TH as shown in FIG.
Either change the value of P1 for each appropriate range of
All you have to do is follow the sequence shown below.

Note that FIG. 13A shows the case where the reference value of P1 is P1=0A, and the preheat pulse width P1 is changed by one step (1H) every 2.0°C. Further, (B) and (C) of the same figure show the case where the reference value of P1 is set to P1=0B or P1=09.

When the sequence shown in FIG. 14 is followed, the procedure is as follows. In this sequence, in order to prevent erroneous head temperature detection and perform more accurate temperature detection, the newly detected temperature Tn is compared with the previous three temperatures (Tn-3, Tn-2, Tn-1). The average head temperature Tm is expressed as Tm = (Tn-3 +Tn-2 +Tn-1 +T
n)/4, and further calculate the average value for the left and right sensors.

In the next step, this value Tm and the previously determined head temperature Tm-1 are compared using the following equation, and correction is performed as follows.

(1) When |Tm −Tm−1 |≦△T (in this example, △T=1°C), the temperature change is within ±1°C, which is shown in Table 1 in FIG. The pulse width of P1 does not change because the temperature range is within the same temperature range. (2) When Tm - Tm-1 > ΔT, the temperature change has shifted to the high temperature side, so the preheat pulse width P1 is reduced by 1H to narrow the pulse width. (3) In the case of Tm −Tm−1 <−△T, the temperature change has shifted to the lower temperature side, so the preheat pulse width P1
Increase by 1H to widen the pulse width.

A flowchart of the sequence described above is shown in FIG. This flowchart is part of the timer interrupt, which enters this routine once every 20 msec. In step S401, the head temperature is read from the two left and right temperature sensors on the four color heads, and the average of the past three temperature data from each sensor is calculated in step S401.
The calculation is performed in step 402. Next, the average of the left and right temperature data is determined for each head. Then, in step S403, according to the relationship between Tm, Tm-1, and ΔT, if the above-mentioned condition (3) is satisfied, P1 is increased by 1H in step S404, and condition (1) is satisfied.
In the case of condition (2), P1 is left unchanged in step S405, and in the case of condition (2), P1 is decreased by 1H in step S406. Note that even when using a table like the one shown in FIG. 13 or a sequence like the one shown in FIG. 14, if the amount of change in P1 is large in one correction, there is a risk of uneven density. Therefore, even if the temperature change becomes larger than the correction range of one pointer, control is performed so that the amount of change in P1 becomes one pointer (1H in this embodiment) at one time.

When using a sequence, the time required to change one pointer during printing (feedback time) is TF = 20 msec. Therefore, 1
The pointer can change about 40 times within a line (about 800 msec). For this reason, the maximum is △Tup
It is possible to cope with a temperature increase of 19.0°C, reducing the occurrence of changes in density over a wide temperature range. The reason why we use the average of four times for temperature detection is to prevent false detections due to sensor noise, etc., to provide smooth feedback, and to keep density fluctuations due to control to the minimum necessary, allowing continuous density changes using the serial printing method. This is to make (connecting lines) less noticeable.

[0060] Using this discharge amount control method, the target discharge amount VD0 = 30.0 (ng/dot) in the above temperature range.
control within a range of ±0.3 (ng/dot). By keeping the ejection amount fluctuations within this range, the density fluctuations that occur during printing on one sheet can be suppressed to approximately ±0.2, and the occurrence of noticeable density unevenness and connecting lines in serial printing methods can be suppressed. can be made so that it does not become a problem.

[0061] Increasing the average number of temperature detections increases resistance to noise and provides smoother changes, but real-time control impairs detection accuracy and makes accurate control impossible. Furthermore, reducing the average number of temperature detections makes the temperature sensitive to noise and causes sudden changes, but real-time control increases detection accuracy and enables more accurate control.

The state (3) is an uncontrolled region, and is assumed to be a case where the head temperature TH is equal to or higher than 44.0°C. In the printing state, for example, when printing continuously at 100% duty (printing at the highest ejection frequency), the head temperature may momentarily reach this range, but the head structure is designed to prevent the temperature from constantly reaching this range. The design and head drive conditions are set. If this condition occurs continuously, it will be determined that it is an abnormal high temperature condition and a recovery action will be taken to deal with it. Further, the pulse width of P1 is set to P1 = 0.187 μsec to suppress heating caused by the preheat pulse and to reduce self-heating due to printing as much as possible.

(Temperature Control) Next, the temperature control sequence will be described in detail. In this embodiment, control is performed on the main body side using left and right sub-heaters located on the head side and left and right temperature sensors located near the discharge heater. FIG. 15 shows the H. A schematic diagram of B is shown. Temperature sensor 8e, sub heater 8d
, a discharge section row 8 in which a discharge (main) heater 8c is arranged.
g. A driving element 8h is formed on the same substrate in a positional relationship as shown in the figure. By arranging each element on the same substrate in this way, the head temperature can be detected and controlled efficiently, and the head can be made more compact and the manufacturing process can be simplified. Also in the same figure, H. The positional relationship of the outer circumferential wall cross section 8f of the top plate that separates B into a region filled with ink and a region not filled with ink is shown. As shown in the figure, the temperature sensor 8e is disposed closer to the ejection port than the outer circumferential wall 8f of the top plate, that is, in an area filled with ink, and close to the ejection port. This makes it possible to efficiently detect the head temperature near the ejection port.

Temperature detection is similar to the discharge amount control method.
The average value is used. At this time, head temperature TH
is the average value of the temperature TR detected from the right sensor and the temperature TL detected from the left sensor (TH = (
TR +TL )/2) is used. Based on this detected temperature, current is sent to the sub-heater on the head side to control the temperature, but the temperature control method is basically an ON/Off control.
This is F method. In other words, the maximum power (1.2 W for each left and right side) is applied until the target temperature T0 = 25.0° C. is reached, the current is cut off when the target temperature is reached, and the current is passed when the temperature drops. The ON/OFF timing is performed every 40 msec. When this timing is lengthened, the width of the ripple becomes larger and the period becomes longer. Furthermore, if this timing is shortened, the width of the ripple becomes smaller and the cycle becomes shorter. With this method, the temperature control ripple width at the target temperature is approximately 2℃.
However, since the temperature detection is based on the average of four times, the temperature control ripple has almost no effect on the discharge amount control. If necessary, an expensive control method such as PID control may be used.

FIG. 16 is a flowchart of the initial 20 degree temperature control routine. In step S2001, set the timer counter to 3.
After setting the temperature to 0 seconds, if the temperature is higher than 20°C, the routine ends (step S2002). If the temperature is lower than 20° C., the head heater is turned on in step S2003. In step S2004, it is checked whether 30 seconds have elapsed on the timer. If 30 seconds have elapsed, the process is abnormally stopped in step S2005, and if not, the process returns to step S2002.

FIG. 17 is a flowchart of the 20 degree temperature control and 25 degree temperature control routines. In step S2101, it is checked whether the head temperature is higher or lower than 20°C. If the temperature is higher than 20°C, turn off the head heater in step S2102.
If the temperature is lower than 20° C., the head heater is turned on in step S2103, and the 20° temperature control routine is completed. Note that step S2 in the 25 degree temperature control routine
Steps 104 to S2106 are also the same as steps S2101 to S2103 in the 20 degree temperature control routine, so the explanation will be omitted.

(HS Table) Here, a method for effectively utilizing the HS control method used in this embodiment will be described. Since this embodiment uses a replaceable head (cartridge type), the user can replace the head at any time, so detailed adjustments by a service person or the like cannot be expected. In addition, since cartridge heads are manufactured by mass production, each head has its own characteristics, and ejection within one head may be affected by variations in the manufacturing process such as the area, resistance value, membrane structure, and nozzle formation of the H and B mentioned above. Since characteristic distribution and discharge hole diameter distribution occur, a method for correcting density unevenness due to variation in discharge amount is required.

A method for correcting the dispersion in ejection amount within one head so as to form an optimal image without unevenness will be described below. When the power is turned on, the R of the head
The table THS is read as HS data along with the ID number, color, and driving conditions as OM information. This table T
Copy the HS on the main unit side.

The THS is determined as follows. HS data is calculated by measuring the diameter distribution of each head under standard driving conditions in advance during the head manufacturing process, and a table of the calculation results is stored as ROM information of the head.

As described above, the HS data table TH
By reading S as head ROM information,
By making it possible to correct unevenness for each head on the main body side, it becomes possible to absorb density unevenness due to variations in ejection amount for each head. Therefore, it has become possible to easily stabilize color image quality even with a main body that uses an exchangeable head. (One-line printing operation) FIG. 18 shows a flowchart showing details of the one-line printing routine in step S24. First, printing control is performed in step S2501. In step S2502, the amount of carriage movement is set. The carriage is advanced in step S2503, and step S25
Set the timer at 04. Paper floating is checked in step S2505, and if paper floating is detected, step S2505 is performed.
It becomes a jam at 06.

[0071] In step S2509, it is determined whether the motor has stopped. If the motor is stopped, step S251
0, and if the motor is running, the timer is checked in step S2511. If the time is up, an error occurs in step S2512; if the time is not up, the process returns to step S2505.

A timer is set in step S2513, and movement of the carriage to the starting position is started in step S2514. In step S2515, one line is printed and the counter is added. In step S2516, it is checked whether the motor has stopped, and if the motor has stopped, the one line printing routine is ended. If the motor is running,
The timer is checked in step S2517. If the time has elapsed, an error occurs in step S2518; if the time has not elapsed, the process returns to step S2516.

FIG. 19 shows the flow of the print control routine of step S2501 in FIG. In step S2601, it is checked whether the mode is RHS mode. If it is the RHS mode, the process advances to step S2602, printing control [1], and if it is not the RHS mode, the process advances to step S2605. Step S2605
Check if it is in OHP mode. If the mode is OHP mode, the process advances to step S2607; otherwise, the process advances to step S2608.

[0074] In step S2607, it is determined whether the reduction mode is selected. If it is the reduction mode, print control [4
], otherwise print control in step S2610 [
Proceed to 5]. In step S2608, it is also checked whether the reduction mode is selected. If it is the reduction mode, the print control in step S2611 [
If not, the process advances to print control [7] of step S2612.

FIG. 20 shows print control in reduced print mode [6]
The flow is shown below. Printing control includes head digit control, ink ejection force control, and head timing control. Here, head digit control will be explained in detail.

The number of nozzles in the recording head is 128. Head digit control is to control ON/OFF of the nozzles of this head in units of 8 nozzles. This 8 nozzle unit is defined as a digit. FIG. 22 is an explanatory diagram thereof. For example, digit 1 is composed of nozzles 1 to 8, and digit 16 is composed of nozzles 121 to 128. There are 16 control digits in one head.

The flow of the head digit control [6] routine is shown in FIG. 21, and an explanatory diagram is shown in FIG. In this routine, when the carriage performs A4 size recording during reduced printing, one line printing is performed 65 times, so digit control is performed 65 times each. During the odd-numbered one-line printing (steps S2801 and S2802), ink is ejected from nozzle 1 to nozzle 64 in step S2805, and ink is not ejected from nozzle 65 to nozzle 128.

In addition, when printing one line for an even number of times (step S2801), the nozzle 6 is turned off in step S2803.
Ink is ejected from nozzles 5 to 128, and no ink is ejected from nozzles 1 to 64. Further, in the 65th one-line printing of the final printing, ink is ejected from the nozzle 81 to the nozzle 128 in step S2804.

FIG. 23 shows print control [1] in RHS print mode.
] Shows the flow of the routine. Printing control includes head digit control, ink ejection force control, and head timing control. Here, head digit control and head timing control will be explained. Description of ink ejection force control will be omitted.

FIG. 24 is a flowchart of the head digit control [1] routine in the RHS print mode, and an explanatory diagram thereof is shown in FIG. In this routine, since the carriage prints one line 12 times during RHS printing, each digit is controlled. 3n+1st time (n=0, 1, 2, 3
) (step S3101), digits 13 to 16 (nozzle 97
to the nozzle 128).

[0081] When printing one line for the 3n+2nd time (step S3103), digit 1 to digit 16 (nozzle 1 to nozzle 128) is printed in step S3104.
Discharge up to For other (3n+3) one-line printing, digits 1 to 4 (nozzle 1 to nozzle 39) are ejected in step S3105.

FIG. 26 is a flowchart of the head timing control [1] routine in the RHS print mode.

[0083] The printing pattern of Bk, C, M, Y is
Set the area to be printed as shown in FIG. 28. Although a detailed explanation of timing control will be omitted, a comparison diagram with normal printing timing is shown in FIG. Figure 27
27(A) shows the print timing in a print mode other than the RHS print mode, and FIG. 27(B) shows the RHS print timing.

[0084] Print control during OHP printing is print control [5]
It is. The flow of this print control [5] routine is shown in Figure 29.
It is. Head digit control [5] is shown in FIG. 30, head nozzle control [5] is shown in FIG. 31, and head digit control [5] and head nozzle control [5] will be explained. In this routine, in order to record on OHP paper, the carriage scans the same area twice and thins out the area for printing. Therefore, when recording A4 size on a carriage, one line printing is performed 66 times, so digit control is performed each time 66 times.

In FIGS. 30 and 31, when performing odd-numbered one-line printing, only the odd-numbered nozzles from nozzle 1 to nozzle 128 (step S3703) are driven (step S3802) to eject ink. Further, when printing one line at an even number, only the even number nozzles from nozzle 1 to nozzle 128 (step S3703) are driven (step S3803) to eject ink. For the 65th one-line printing, only the odd-numbered nozzles from nozzle 81 to nozzle 128 (step S3702) are driven (step S3802) to eject ink. Further, for the 66th one-line printing, only the even-numbered nozzles from nozzle 81 to nozzle 128 (step S3702) are driven (step S3803) to eject ink. Figure 32, Figure 33
is an explanatory diagram thereof.

Print control during OHP reduction printing is print control [
4]. FIG. 34 shows the flow of this print control [4] routine. Head digit control [4] is shown in FIG. 35, head nozzle control [4] is shown in FIG. 36, and head digit control [4] and head nozzle control [4] will be explained. In this routine, in order to record on OHP paper, the carriage scans the same area four times, thins out the area, and prints. Therefore, when recording A4 size, the carriage prints one line 130 times, so digit control is performed 130 times each.

4n+1 of the 1st time (n=0, 1,...)
For line printing, from nozzle 1 to nozzle 64, that is, from digit 1 to digit 8 (step S42
05) only drive odd numbered nozzles (step S4302)
and ejects ink. 4n+2nd time (n=0, 1,
), only the even-numbered nozzles from nozzle 1 to nozzle 64 are driven (step S4303).
) and eject ink. 4n+3rd time (n=0, 1
. 4n+4
When printing one line for the first time (n=0, 1,...),
Only the even-numbered nozzles from nozzle 65 to nozzle 128 are driven (step S4303) to eject ink. 37 and 38 are explanatory diagrams thereof.

For the 129th one-line printing, only the odd-numbered nozzles from nozzle 81 to nozzle 128, that is, from digit 11 to digit 16 (step S4204) are driven (step S4302) to eject ink. For the 130th one-line printing, only the even-numbered nozzles from nozzle 81 to nozzle 128 are driven (step S
4303) and ejects ink. FIG. 39 is an explanatory diagram thereof.

(Control Configuration) Next, a control configuration for executing the above-described recording control flow will be explained with reference to FIG. In the same figure, 60 is a CPU, 61 is a CPU
A program ROM 62 stores a control program executed by the U 60, and a backup RAM 62 stores various data. 63 is a main scanning motor for conveying the recording head, and 64 is a sub-scanning motor for conveying recording paper, which is also used for suction operation by a pump. 65 is a wiping solenoid, 66 is a paper feed solenoid used for paper feeding control, 67 is a cooling fan, and 68 is a paper width detection LED that is turned on during a paper width detection operation. 69 is a paper width sensor;
70 is a paper floating sensor, 71 is a paper feed sensor, 72 is a paper discharge sensor, and 73 is a suction pump position sensor that detects the position of the suction pump. 74 is a carriage HP sensor that detects the home position of the carriage; 75 is a door open sensor that detects the opening/closing of the door; 76 is a manual feed button sensor that detects the press of the manual feed button; and 77 is the OHP button sensor that detects the press of the OHP button. It is.

78 is a gate array that controls the supply of print data to the heads of four colors; 79 is a head driver that drives the heads; 8a is an ink cartridge for the four colors;
8b is a recording head for four colors; here, 8a, 8b
Black (Bk) is shown as a representative. The ink cartridge 8a has an ink remaining amount sensor 8f that detects the remaining amount of ink. The head 8b includes a main heater 8c for ejecting ink, a sub-heater 8d for controlling the temperature of the head, and a head temperature sensor 8e for detecting the head temperature.
, has a ROM 854 that stores head characteristic information.

FIG. 41(A) is a diagram showing the external appearance of the inkjet cartridge of this embodiment. Also, the same figure (B
) is a diagram showing details of the printed board 85 in FIG. In FIG. 41(B), 851 is a printed circuit board, 85
2 is an aluminum heat sink, 853 is a heater board consisting of a heating element and a diode matrix, 854 is an EEPROM (non-volatile memory) that stores density unevenness information, etc. in advance;
and 855 are contact electrodes that form a joint with the main body. Note that the linear ejection port group is not illustrated here.

In this way, the inkjet recording head 8
An EEPROM 854 for storing density unevenness information specific to each recording head is mounted on a printed circuit board 851 including a heating element and a drive control section (b). By doing this, when the recording head 8b is attached to the main unit, the main unit reads information regarding the recording head characteristics such as density unevenness from the recording head 8b, and based on this information performs predetermined control to improve the recording characteristics. I do. This makes it possible to ensure high image quality.

FIGS. 42A and 42B are diagrams showing the main circuit configuration on the printed circuit board 851 of FIG. 41. here,
The circuit configuration inside the heater board 853 is shown within the dashed-dotted line.
It has a matrix structure of ×M (here, 16×8). That is, these heating elements 857 are driven in time division for each block as shown in FIG. 43, and the supply amount of driving energy is controlled by changing the pulse width (T) applied to the segment (seg) side. This is achieved by controlling the

FIG. 42(B) shows the EEPRO of FIG. 41(B).
It is a diagram showing an example of M854, and information such as density unevenness related to the present example is stored. These pieces of information are output to the main device through serial communication in response to a request signal (address signal) D1 from the main device. The entire apparatus to which the present invention is applicable will be explained.

FIG. 44 is a perspective explanatory diagram of the configuration of this embodiment, FIG.
5 is an explanatory cross-sectional view thereof. First, the overall configuration will be explained. This device consists of a reading device R and a recording device P.

The structure of the reading device R is such that a reading means 1 is provided on a reading carriage 2, and this carriage 2 is movable back and forth in the main scanning direction (direction of arrow a). Further, the carriage 2 is attached to a reading unit 3, and the unit 3 is configured to be able to reciprocate in the sub-scanning direction (arrow b direction).

Therefore, when the original 5 is placed face down on the original platen glass 4 attached to the top of the apparatus, the original is fixed with the cover 6, and the copy switch (not shown) is pressed, the carriage 2 moves in the main scanning direction to read one line of the document, and transmits the information via the signal cable 7 to a control system (not shown). When the reading of one line is completed as described above, the carriage 2 is returned to the home position, the reading unit 3 is moved one line in the sub-scanning direction, and the next line and subsequent lines are read in the same manner as above. .

The recording apparatus P is configured such that a recording means 8 is mounted on a recording carriage 9, and a recording sheet 11 is conveyed to the position of the recording means 8 by a sheet conveying means 10.

Therefore, when the reading signal from the reading device R is transmitted via the signal cable 7, the recording sheet 11
is conveyed in the direction of arrow c by the conveying means 10, and the sheet 11
When the recording carriage 9 is conveyed to the recording position, the recording carriage 9 is moved to the position shown in FIG.
3, the recording means 8 is driven in accordance with the image signal in synchronization with this movement, and the recording sheet 1 is
Record the image in 1. When recording for one line is completed, the recording sheet 11 is conveyed by one line in the direction of arrow c, recording is performed in the same manner, and the sheet 11 after recording is discharged to the discharge tray 12.

[0100] Here, a part of the bottom part of the reading unit 3 is configured to protrude so as to be lower than the highest part of the recording device P,
One end of a signal cable 7 is connected and fixed to this portion.

FIG. 46 is a schematic perspective view of an inkjet recording apparatus. In the figure, the recording sheet 11 is conveyed by conveying rollers 10c and 1 driven by a stepping motor.
It is configured to be transported by 0d. 8a is a black, cyan, magenta, and yellow ink cartridge, and an inkjet recording head 8 is located at the bottom end.
b (not shown) is attached. Recording head 8b
is mounted on the carriage 9, and is moved to the main scanning rail 9a via the belt 9c and pulley by the drive of the carriage motor.
It is configured to scan back and forth along the With the above configuration, an image is formed by ejecting ink onto the recording sheet 11 while the recording head 8b moves. In addition, if necessary, an ink recovery system unit (cap unit 300)
, pump unit 500, etc.) to eliminate clogging of nozzles.

(Head Temperature Correction) Next, the features of this embodiment will be explained in detail. In this embodiment, as described above, during normal printing, the left and right average value (TH = [THL+THR]/2) is used as the head temperature TH for head drive control. Furthermore, when printing the last line or reducing printing, depending on the position and number of nozzles used,
Corrected temperature TH' calculated by weighting the temperature detected by the left and right temperature sensors = (XTHL + YTHR) /
The head drive control is performed based on (X+Y).

When only the left half of the head nozzle is used, the head temperature shows a temperature distribution as shown in FIG. This tendency becomes more pronounced as the printing duty becomes higher. During printing, the temperature sensor on the left always shows a high temperature, and the temperature sensor on the right always shows a low temperature. When the head is driven using the head temperature TH measured in this state, the temperature THL (TH
In order to control the temperature lower than L>TH),
Control to increase the discharge amount, that is, preheat pulse P
Control is activated to lengthen the pulse width of 1. Normally, the control would have to work to reduce the discharge amount, so the control would diverge. In addition, preheat pulse P1
As the pulse width becomes longer, the temperature rise due to discharge becomes larger, so the temperature difference between the left and right sides becomes even larger.

Therefore, in this embodiment, in order to eliminate the above-mentioned vicious cycle, the corrected temperature calculated by multiplying the temperatures detected by the left and right temperature sensors as described above by weight: TH'=
It is controlled by (XTHL+YTHR)/(X+Y). Here, when discharging from the left half nozzle above,
= 4, Y = 1 in advance on the main body side. For example, when printing with a printing duty of 50%, the temperature detected on the first line is THLMAX = 40℃, TH
When RMAX = 30℃, (1) In normal control, the pulse width of preheat pulse P1 is controlled based on TH = (40 + 30) / 2 = 35℃, so THLM
The difference from AX is 5°C. (2) In the control of this embodiment, the pulse width of the preheat pulse P1 is controlled based on TH'=(160+30)/5=38°C, so TH
The difference from LMAX is 2°C, which reduces the difference from the true temperature. Therefore, more accurate head drive control can be performed.

(Second Embodiment) Next, a second embodiment of the present invention will be described. This embodiment performs head temperature correction as part of temperature control in head driving, and will be described with reference to a case where it is applied to a monochrome printer.

In this device, when printing the head temperature TH, the average value (TH
L=[THLN-2 +THLN-1 +THLN]
/3) is used to control the drive of the temperature control sub-heaters on the left and right sides of the head. At this time, the temperature difference detected by the left and right temperature sensors is detected depending on the position and number of nozzles used, and the power is controlled to weight the energy given to the sub-heater to eliminate temperature distribution. be.

[0107] When using only the left half of the head nozzle,
The head temperature shows a temperature distribution as shown in FIG. 47 shown above. This tendency becomes more pronounced as the printing duty becomes higher. During printing, the temperature sensor on the left always shows a high temperature, and the temperature sensor on the right always shows a low temperature. By driving the sub-heater taking into account the head temperature difference △TH measured in this state, the head temperature THL on the nozzle side (left half) that is discharging is set to a low value taking into account the head temperature difference △TH. Set the temperature control temperature to lower the power of the sub-heater, and increase the power by setting a high temperature control temperature that takes into account the head temperature difference △TH for the head temperature THR on the side of the nozzle that is not discharging (right half). By doing this, we are trying to eliminate the temperature distribution between the left and right sides.

[0108] In this way, the power is controlled by applying weight to the left and right sub-heaters by detecting the difference in temperature detected by the left and right temperature sensors. When discharging using the left half nozzle described above, start at pre-printing temperature control TH = 35°C,
When printing with a printing duty of 50%, the temperature detected on the first line is THLMAX = 45℃, THRMAX =
If the temperature is 35℃, △TH = (THLMAX -TH
RMAX ) = 10°C, but (1) in normal control, the target temperature control temperature on the left side THL = 35°C, the target temperature control temperature on the right side THR = 35°C, and the control is unchanged from before printing. (2) In the control of this embodiment, the target temperature control temperature on the left side THL=TH -△TH /2=3
Target temperature control temperature THR on the right side of 0℃=TH +△TH /2
= 40° C., and by changing the target controlled temperature according to the difference from the true temperature, control is performed to reduce the temperature difference between left and right printing. In this method as well, a table corresponding to the position and number of nozzles used for printing is prepared in advance on the main body side in correspondence with ΔTH, and the table is controlled.

(Third Embodiment) Next, a third embodiment of the present invention will be described. In this embodiment, P of the head drive is
The head temperature correction is performed in WM control, and the case where it is applied to a color copying machine will be explained. The configuration of this embodiment is basically the same as that of the first embodiment.

[0110] Since color copying machines drive the printer section according to image signals sent from the reader, the relationship between the print area and the print width of the head is not necessarily a positive multiple of the print width; I had to print with an odd nozzle. Further, an inkjet recording apparatus using a serial printing method is designed so that paper feeding accuracy is stable at normal feeding (head width). For this reason, if you change the paper feed especially when reducing, the feed accuracy will drop and connecting lines will occur, disturbing the image, so print twice for each paper feed.
Pass printing is enabled. In such a case, it is necessary to print by changing the number of ejection nozzles of the head. for example,
At the time of 50% reduction, 2-pass printing is performed by alternately using the 64 left and right nozzles.

Therefore, in the third embodiment, a control method is used in which the drive pulses are changed (for example, for each block) based on the left and right temperature difference ΔTH detected by the left and right temperature sensors. In this device, the head temperature: TH is the average value of the left sensor and right sensor three times each during printing (THL = [T
HLN-2 +THLN-1 +THLN ]/3) is used to control the drive of the head. At this time, the structure is such that the temperature difference detected by the left and right temperature sensors is detected depending on the position and number of nozzles used, and drive control is performed to eliminate temperature distribution by weighting the drive pulses given to the head. .

When only the left half of the head nozzle is used, the head temperature shows a temperature distribution as shown in FIG. 47 shown above. This tendency becomes more pronounced as the printing duty becomes higher. During printing, the temperature sensor on the left always shows a high temperature, and the temperature sensor on the right always shows a low temperature. By driving the head in consideration of the head temperature difference ΔTH measured in this state, in other words, by setting a short pulse for the head drive pulse P1L on the nozzle side (left half) that is ejecting, the ejection amount can be controlled. By setting a long pulse for the head drive pulse P1R on the side of the nozzle that is not ejecting (right half) and increasing the ejection amount (increasing the temperature), the left and right ejection amount (temperature) distribution is eliminated. ing. Do the same thing when using only the right half of the head nozzle. Note that FIG. 48 shows a pulse waveform during PWM control.

[0113] In this way, the power is controlled by weighting the left and right drive blocks by detecting the difference in temperature detected by the left and right temperature sensors. When ejecting from the left half nozzle described above, the drive pulse P1 = 1.87 μsec, the pre-printing temperature control TH = 25°C starts, and the printing duty is 5.
The temperature detected on the first line when 0% is printed is T
If HLMAX = 45℃, THRMA = 35℃, △
TH = (THLMAX - THRMAX) = 10℃
(1) In normal control, the left side preheat pulse width P1L=P1 μsec and the right side preheat pulse width P1R=P1 μsec, and the control is unchanged from before printing. In other words, it is controlled by P1. (2) In the control of this embodiment, △P1 = P1 ・△TH /20°C, and the left preheat pulse width P1L = (P1 - △P1 ) μsec
Right side preheat pulse width P1R=(P1 +△P
1) As μsec, the driving conditions are changed depending on the temperature difference between the left and right sides, and control is performed so as to reduce the difference in ejection amount between left and right prints. In other words, it is controlled by (P1 ±△P1).

Note that when ΔTH = 20° C. or more, control is impossible and an error occurs. Further, in the third embodiment, a preheat pulse was supplied to the nozzles that do not eject in order to increase the temperature, but control may be performed so that the preheat pulse is not supplied to the nozzles that do not eject.

(Others) The present invention particularly relates to means for generating thermal energy as energy used for ejecting ink in an inkjet recording system.
For example, the present invention provides an excellent effect in a recording head or recording apparatus that is equipped with an electrothermal converter (for example, an electrothermal converter, a laser beam, etc.) and uses the thermal energy to cause a change in the state of the ink. This is because such a system can achieve higher recording density and higher definition.

[0116] For its typical configuration and principle, see, for example, US Pat. No. 4,723,129 and US Pat.
Preferably, it is carried out using the basic principles disclosed in the '796 specification. This method can be applied to both the so-called on-demand type and continuous type, but
In particular, in the case of the on-demand type, an electrothermal transducer is placed corresponding to the sheet holding the liquid (ink) or the liquid path, and the electrothermal transducer is placed at a temperature that rapidly exceeds nucleate boiling, corresponding to the recorded information. By applying at least one drive signal that provides a rise, the electrothermal transducer generates thermal energy that causes film boiling on the thermally active surface of the recording head, resulting in a liquid ( This is effective because it can form air bubbles within the ink. The growth and contraction of these bubbles causes the liquid (ink) to be ejected through the ejection opening.
Form at least one drop. It is more preferable to use this drive signal in a pulse form, since the growth and contraction of bubbles can be carried out immediately and appropriately, so that ejection of liquid (ink) with particularly excellent responsiveness can be achieved. This pulse-shaped drive signal is described in U.S. Pat. No. 4,463,359 and U.S. Pat.
262 is suitable. Further, if the conditions described in US Pat. No. 4,313,124 concerning the temperature increase rate of the heat acting surface are adopted, even more excellent recording can be achieved.

[0117] In addition to the configuration of the recording head that combines ejection ports, liquid paths, and electrothermal converters (straight liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned specifications, U.S. Pat. No. 4,558,333 and U.S. Pat. No. 4 disclose a configuration in which a heat acting part is arranged in a bending region.
A configuration using the specification of No. 459600 is also included in the present invention. In addition, Japanese Patent Application Laid-open No. 123670 of 1982 discloses a configuration in which a common slit is used as a discharge part for a plurality of electrothermal converters, and a hole that absorbs pressure waves of thermal energy is disclosed. The present invention is also effective as a configuration based on Japanese Patent Application Laid-Open No. 138461 of 1982, which discloses a configuration in which the discharge portion corresponds to the discharge portion.

Furthermore, a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus can be produced by combining a plurality of recording heads as disclosed in the above-mentioned specification. Either a configuration that satisfies the length or a configuration as a single recording head formed integrally may be used, but the present invention can more effectively exhibit the above-mentioned effects.

[0119] In addition, a replaceable chip-type recording head that is attached to the apparatus main body enables electrical connection with the apparatus main body and ink supply from the apparatus main body, or a print head that is integrated into the print head itself. The present invention is also effective when a cartridge type recording head is used.

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

Furthermore, the recording mode of the recording apparatus is not limited to a recording mode of only mainstream colors such as black, but may also include a recording head that is configured integrally or a combination of a plurality of recording heads, or multiple colors of different colors or The present invention is also extremely effective for devices equipped with at least one of the following: , full color by color mixing.

[0122] In the embodiments of the present invention described above, explanations are made using liquid ink, but the present invention can be applied to ink that is solid at room temperature or ink that is in a soft state at room temperature. Can be used. The above-mentioned inkjet device generally adjusts the temperature of the ink itself within the range of 30°C to 70°C to keep the viscosity of the ink within a stable ejection range. It is sufficient if the ink is liquid. In addition, the temperature rise caused by thermal energy can be actively prevented by using the energy to change the state of the ink from a solid state to a liquid state, or an ink that solidifies when left standing is used to prevent ink evaporation. In any case, the ink may be liquefied by application of thermal energy in accordance with the recording signal and ejected as liquid ink, or the ink may have already begun to solidify by the time it reaches the recording medium. The present invention is also applicable to the use of ink that is liquefied for the first time. In such a case, the ink is held in a liquid or solid state in the recesses or through holes of the porous sheet, as described in JP-A-54-56847 or JP-A-60-71260. It may also be in a form that faces the electrothermal converter. In the present invention, the most effective method for each of the above-mentioned inks is to implement the above-mentioned film boiling method.

[0123]

According to the present invention, in an inkjet recording device that uses thermal energy, the temperature of the head can be adjusted by changing the drive control (temperature control method, drive pulse, etc.) of the head depending on the number of nozzles used in the head. It is possible to eliminate the distribution and reduce the variation in discharge amount. This makes it possible to eliminate density unevenness and connecting lines, and to stabilize the density and color balance during final line printing and reduced printing.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing main control of an inkjet recording apparatus that is an embodiment of the present invention.

FIG. 2 is a flowchart showing main control of an inkjet recording apparatus that is an embodiment of the present invention.

FIG. 3 is a flowchart showing main control of an inkjet recording apparatus that is an embodiment of the present invention.

FIG. 4 is a flowchart showing details of an initial jam check routine in step S3.

FIG. 5 is a flowchart showing details of a head information reading routine in step S5.

FIG. 6 is an explanatory diagram of a divided pulse width modulation driving method.

FIG. 7 is an explanatory diagram of a head structure used in this example.

FIG. 8 is a diagram showing the relationship between table pointer TA1 and main heat pulse width P3 determined from TA1.

FIG. 9 is a diagram showing the relationship between table pointer TA3 and preheat pulse width P1.

FIG. 10 is a diagram showing the relationship between preheat pulse width P1 and discharge amount VD.

FIG. 11 is a diagram showing the relationship between head temperature TH and ejection amount VD.

FIG. 12 is a diagram showing the relationship between the head temperature and the ejection amount, showing how the ejection amount is controlled with respect to the head temperature.

[Figure 13] Head temperature TH and preheat pulse width P1
FIG.

FIG. 14 is a diagram showing a sequence for setting the preheat pulse width P1.

FIG. 15 is a diagram showing the positional relationship of the temperature sensor, sub-heater, and ejection (main) heater of the head used in this embodiment.

FIG. 16 is a flowchart of an initial 20 degree temperature control routine.

FIG. 17 is a flowchart of a 20 degree temperature control routine and a 25 degree temperature control routine.

FIG. 18 is a flowchart showing details of a one-line printing routine in step S24.

19 is a flowchart of the print control routine of step S2501 in FIG. 18. FIG.

FIG. 20 is a flowchart of print control [6] routine in reduced print mode.

FIG. 21 is a flowchart of the head digit control [6] routine.

FIG. 22 is an explanatory diagram of head digit control [6].

FIG. 23 is a flowchart of the print control [1] routine in the RHS print mode.

[Figure 24] Head digit control in RHS print mode [1]
] This is a flowchart of the routine.

[Figure 25] Head digit control in RHS print mode [1]
] is an explanatory diagram.

[Figure 26] Head timing control in RHS print mode [
1] This is a flowchart of the routine.

FIG. 27 is a diagram showing print timing.

FIG. 28 is a diagram showing areas in which Bk, C, M, and Y printing patterns are printed.

FIG. 29 is a flowchart of a print control [5] routine during OHP printing.

FIG. 30 is a flowchart of the head digit control [5] routine.

FIG. 31 is a flowchart of the head nozzle control [5] routine.

32 is an explanatory diagram of nozzle driving performed by head digit control [5] in FIG. 30 and head nozzle control [5] in FIG. 31;

33 is an explanatory diagram of nozzle driving performed by head digit control [5] in FIG. 30 and head nozzle control [5] in FIG. 31. FIG.

FIG. 34 is a flowchart of a print control [4] routine during OHP reduction printing.

FIG. 35 is a flowchart of the head digit control [4] routine.

FIG. 36 is a flowchart of the head nozzle control [4] routine.

37 is an explanatory diagram of nozzle driving performed by head digit control [4] in FIG. 35 and head nozzle control [4] in FIG. 36. FIG.

38 is an explanatory diagram of nozzle driving performed by head digit control [4] in FIG. 35 and head nozzle control [4] in FIG. 36. FIG.

39 is an explanatory diagram of nozzle driving performed by head digit control [4] in FIG. 35 and head nozzle control [4] in FIG. 36. FIG.

FIG. 40 is a block diagram showing a control configuration for executing a recording control flow.

FIG. 41 is a diagram illustrating the inkjet cartridge of this embodiment.

FIG. 42 is a diagram illustrating a main circuit configuration on a printed circuit board 851.

FIG. 43 is a timing chart for driving the heating element 857 in a time-division manner for each block.

FIG. 44 is a perspective explanatory diagram of the configuration of this embodiment.

FIG. 45 is a cross-sectional explanatory diagram of this embodiment.

FIG. 46 is a schematic perspective view of an inkjet recording device.

FIG. 47 is an explanatory diagram showing the temperature distribution of head temperature.

FIG. 48 is a waveform diagram showing pulse waveforms during PWM control.

[Explanation of symbols]

P Recording device R Reading device HP Home position SP start position 1 Reading means 2 Reading carriage 3 Reading unit 8 Recording means 8a Ink cartridge 8b Recording head 8c Discharge (main) heater 8d Sub heater 8e Temperature sensor 9 Recording carriage 9a Main scanning rail 9b Drive pulley 9c Timing belt 9d Recording carriage motor 10 Sheet conveyance means 60 CPU 853 Heater board 854 EEPROM

Claims (10)

[Claims] 1. An inkjet recording apparatus that uses an inkjet recording head equipped with a plurality of ejection heaters corresponding to ink ejection ports and a temperature sensor, and determines driving conditions for the recording head based on a temperature detected by the temperature sensor. An inkjet recording apparatus characterized in that driving conditions for the recording head are changed depending on ejection ports used for recording. 2. The inkjet recording apparatus according to claim 1, wherein driving conditions for the recording head are changed depending on the position or number of ejection ports used for recording. 3. The inkjet recording apparatus according to claim 1, wherein the pulse width of the drive pulse supplied to the ejection heater is determined based on the temperature detected by the temperature sensor. 4. The inkjet recording according to claim 1, wherein the driving pulse is divided into two or more, and the width of at least one of the divided pulses is determined based on the temperature detected by the temperature sensor. Device. 5. The temperature sensor includes a plurality of temperature sensors, and the driving conditions for the print head are changed based on a temperature obtained by weighting a plurality of detected temperatures according to the ejection ports used for printing. 1. The inkjet recording device according to 1. 6. The inkjet recording apparatus according to claim 1, wherein the plurality of ejection heaters and the temperature sensor are formed on the same chip. 7. Using an inkjet recording head equipped with a plurality of ejection heaters corresponding to ink ejection ports, a plurality of temperature control heaters, and a plurality of temperature sensors, the An inkjet printing apparatus that determines driving conditions for a printhead, the inkjet printing apparatus changing the driving conditions for the printhead depending on the ejection ports used for printing. 8. The inkjet recording apparatus according to claim 7, wherein conditions of drive pulses supplied to the plurality of temperature control heaters are changed based on the temperatures detected by the plurality of temperature sensors. 9. The inkjet recording apparatus according to claim 7, wherein the pulse width of the drive pulse supplied to the ejection heater is determined based on the temperatures detected by the plurality of temperature sensors. 10. The inkjet recording apparatus according to claim 7, wherein the plurality of ejection heaters, the plurality of temperature control heaters, and the plurality of temperature sensors are formed on the same chip.