JP5864915B2 - Inkjet recording apparatus and inkjet recording method - Google Patents

Description

  The present invention relates to an ink jet recording apparatus and an ink jet recording method.

  The ink jet recording apparatus performs recording by repeating an operation of scanning a recording head for ejecting ink relative to the recording medium and a transporting operation of transporting the recording medium in a direction intersecting the direction of scanning the recording head. An image is formed on the medium. In such image formation, in order to achieve high image quality, multi-pass recording is widely employed in which the same area of the recording medium is scanned with the recording head multiple times to complete the image. A recording operation is performed while scanning in both directions (hereinafter also referred to as bidirectional printing).

  The ink ejected from the recording head lands on a recording medium such as paper, and the pigment or dye is fixed on the recording medium as the solvent volatilizes. However, the speed at which the solvent in the ink volatilizes depends on the environment such as temperature and humidity, and the conditions such as the amount and density of the ejected ink. There was a possibility that the fixing of was not stable. Therefore, it is known to provide fixing means for heating the recording medium in order to fix the ink reliably (Patent Document 1).

  Japanese Patent Application Laid-Open No. 2004-133867 discloses an ink jet recording having a spare heater in which a plurality of heaters positioned upstream in the conveyance direction of the recording area are arranged in parallel and a heater in which a plurality of heaters located in the conveyance direction downstream of the recording area are arranged in parallel. An apparatus is disclosed. By performing ON / OFF control of the preliminary heater and the heater according to the size of the recording medium and the printing rate of the image recorded on the recording medium strip, the image can be fixed early while suppressing energy consumption. It is stated that you can.

JP 2003-326680 A

  By the way, in order to achieve further high-speed recording and high image quality required in recent years, it is necessary to perform image formation by scanning the recording head at high speed while performing multipass recording. When the recording head is scanned at high speed when performing multi-pass printing, the folded portion from the forward path (hereinafter also referred to as the first path) to the return path (hereinafter also referred to as the second path) is the first path and the second path. The time difference between the two paths becomes shorter. For this reason, there is a possibility that the ink droplet landed in the first pass will land in a state where the ink droplet landed in the first pass is not sufficiently dried.

  Patent Document 1 does not consider high-speed recording by multi-pass recording that can achieve high speed and high image quality as required in recent years. Therefore, even if the heating control of the recording medium is performed according to the size of the recording medium and the recording data as in Patent Document 1, the second pass in the state where the ink droplets of the first pass are not sufficiently dried at the folded portion. A pass may be printed. When ink is ejected in a state where it is not sufficiently dried, a so-called beading phenomenon occurs in which the ink droplets that have landed first are attracted to the ink droplets that have landed later and aggregate. On the other hand, in the vicinity of the center of the recording area where there is a certain time difference between the first pass and the second pass, the ink droplets discharged in the forward pass are dried and then the ink droplets in the return pass are discharged. It is difficult to occur.

  If the size of the beading phenomenon occurs between the edge and the center of the recording area, it appears as image density unevenness, leading to a reduction in image quality. Furthermore, since the size of the ink jet recording apparatus has increased and the width of the recording medium has increased, there is a difference between the timing at which ink droplets are ejected in the first pass and the timing at which ink droplets are ejected in the second pass. There is a tendency for the beading phenomenon to become more and more pronounced.

  Further, if the recording medium is heated to such an extent that the beading phenomenon does not occur in the folded portion using a fixing heater as disclosed in Patent Document 1, the vicinity of the center of the image forming area is heated more than necessary. Therefore, there is a concern that the recording medium may be wrinkled or altered. Furthermore, it is necessary to heat the fixing heater more than necessary, resulting in wasted power consumption.

  The present invention has been made in view of the above problems, and is capable of obtaining a highly reliable image without occurrence of density unevenness without causing wrinkles or alteration in the recording medium even when recording is performed at high speed. An object of the present invention is to provide an inkjet recording apparatus having a high image quality.

Accordingly, the present invention provides a recording head that ejects ink based on input image data, a scanning unit that scans the recording head in a scanning direction with respect to the recording medium, and a heating unit that is used to heat the recording medium. Fixing means comprising a plurality of heating means arranged along the direction, and control means for drivingly controlling each of the plurality of heating means corresponding to the image forming area in order to heat the image forming area of the recording medium; And the control means corresponds to the heating means corresponding to the distance from the edge of the image forming area when the recording head is scanned a plurality of times with respect to the unit area on the recording medium to form an image. The plurality of heating units corresponding to the image forming area of the recording medium are driven and controlled so that the set temperature is lowered .

  According to the present invention, even if high-pass multi-pass printing is performed, heating control can be performed so that ink droplets are fixed on the image forming area of the recording medium, so that the beading phenomenon can be prevented and image unevenness can be prevented. Can be prevented. Furthermore, it is possible to provide a highly reliable ink jet recording apparatus that can prevent the area of the recording medium from being overheated and can prevent wrinkling and deterioration of the recording medium.

FIG. 2A is a schematic perspective view of an ink jet recording apparatus. FIG. 2B is a schematic sectional view of the ink jet recording apparatus. FIG. 2C is a schematic top view of the ink jet recording apparatus. FIG. 3 is a perspective view of a recording head substrate according to the present invention. It is a flowchart explaining the control flow in 1st embodiment. FIG. 3 is a schematic diagram illustrating an image forming area of a recording medium and a fixing heater. It is a graph which shows the distance from the edge part of an image formation area, and temperature. It is a graph which shows the preset temperature of the individual heater in 1st embodiment. It is a flowchart explaining the control flow in 2nd embodiment. (A) is explanatory drawing which shows the relationship between a printing scan and a printing duty. (B) is explanatory drawing which shows the maximum recording duty according to a count position. (A) It is a graph which shows the maximum recording duty from the edge part by the side of HP of an image formation area to a center part. (B) It is a graph which shows the maximum recording duty from the edge part by the side of BP of an image formation area to a center part. It is a graph which shows the relationship between the recording duty for every position from the edge part of an image formation area, and the setting temperature of an individual heater. It is a graph which shows the preset temperature of the individual heater in 2nd embodiment. It is a flowchart explaining the control flow in 3rd embodiment. It is a control block diagram of an inkjet recording device.

  The ink jet recording apparatus can be used for performing a recording operation on a recording medium by discharging ink. Specific examples of applicable equipment include office equipment such as printers, copiers, and facsimile machines, and industrial production equipment. The present invention is particularly effective in a device that performs high-speed recording on a large recording medium. By using such an ink jet recording apparatus, recording can be performed on various recording media such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, and ceramics.

  “Recording” used in this specification means not only giving an image having a meaning such as a character or a figure to a recording medium but also giving an image having no meaning such as a pattern. I will do it.

  Furthermore, “ink” is to be interpreted widely, and is applied to a recording medium to be used for forming an image, pattern, pattern, etc., processing the recording medium, or processing the ink or the recording medium. Say liquid.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, components having the same function may be given the same reference numerals in the drawings, and the description thereof may be omitted.

(Inkjet recording device)
FIG. 1A is a schematic perspective view of an ink jet recording apparatus 100 according to the present invention.
FIG. 1B is a schematic sectional view of the ink jet recording apparatus according to the present invention. FIG. 1C is a schematic top view of the ink jet recording apparatus according to the present invention.

  The recording head 1 includes a plurality of ejection openings for ejecting ink on a surface facing a recording medium support member 4 (hereinafter also referred to as a platen). The recording head 1 is attached to the carriage 104, and the carriage 104 moves along the guide 103 by a carriage driving means (not shown), so that the recording head 1 reciprocates relative to the recording medium 2 in the directions of arrows a and b. The recording operation is performed. Hereinafter, a direction indicated by arrows a and b is referred to as a scanning direction. Further, the pair of transport rollers 5 provided so as to sandwich the recording medium 2 rotate to transport the recording medium in the sub-scanning direction (arrow c direction) which is a direction orthogonal to the scanning direction. Image formation is performed by repeating the recording operation of scanning the recording head 1 to eject ink and the transporting operation of transporting the recording medium 2 in the sub-scanning direction. In such an ink jet recording apparatus, so-called multi-pass recording is performed in which a recording head is scanned a plurality of times to perform the recording operation on the same area of the recording medium in order to form a high-definition image. The platen 4 is positioned below the recording head 1 and holds the recording medium 2 so that the distance between the recording medium and the recording head is appropriate.

  The recording head 1 is connected to an ink tank (not shown), and ink is replenished to the recording head 1 via an ink supply tube or the like.

  Further, the ink jet recording apparatus is provided with a fixing heater 8 (fixing means) used for heating the area of the recording medium on which the ink ejected from the recording head 1 is landed. By heating the recording medium with such a fixing heater 8, volatilization of moisture and organic solvent in the ink can be promoted, and ink droplets can be fixed on the recording medium. As the fixing heater 8, an irradiation type heat source or means for irradiating energy rays such as infrared rays and ultraviolet rays can be used. When an irradiation type heat source is used, it is preferably provided so as to be covered with a covering portion 7 as shown in FIG. FIG. 1B shows a configuration in which the fixing heater 8 is provided above the recording medium 2. However, the fixing heater 8 may be integrated with the platen 4 to be provided below the recording medium.

  The fixing heater 8 according to the present invention is provided with a plurality of individual heaters (heating means) arranged in a line in the main scanning direction in FIG. FIG. 1C shows an example in which 26 individual heaters are arranged. The fixing heater 8 is provided by arranging 26 individual heaters, from the left end side (first side) of the recording medium toward the right end side (second side) of the recording medium. 8a to 8z. The left end of the recording medium is the position where the recording head is held during non-recording operation, so it is the home position side (HP side), and the right end of the recording medium is the side where the recording head is turned back, so Also referred to as the side (BP side). Hereinafter, scanning the recording head from the first side toward the second side is referred to as a forward path (first pass), and scanning the recording head from the second side toward the first side is referred to as a return path. (Second pass).

  As shown in FIG. 1C, independent temperature control can be performed by the heater controller as a plurality of individual heaters, and the recording medium can be heated with high accuracy. A temperature sensor for confirming whether the heating temperature on the recording medium is a target temperature is provided, and the heat generation condition of the fixing heater 6 can be optimally controlled by always feeding back the measured temperature to the heater controller. it can. Such a temperature sensor may be provided for each individual heater, or may be provided only for a specific individual heater for relative temperature control. Furthermore, the temperature of the recording medium may be further controlled by installing a cooling fan in the ink jet recording apparatus and providing a heat dissipation mechanism.

(Recording head)
Next, a schematic diagram of a recording head substrate 41 used in the recording head 1 that can be mounted on the inkjet recording apparatus 100 according to the present invention is shown. Here, the recording head substrate 41 using an electrothermal conversion element that discharges ink using heat will be described as an example, but the present invention can also be applied to a piezoelectric element (piezo element).

  FIG. 2 is a perspective view of a recording head substrate 41 disposed on the surface of the recording head 1 facing the recording medium 2. The recording head substrate 41 includes a base body 15 including a recording element 12 that generates thermal energy used for discharging a liquid, and a flow path wall member 14 provided on the base body 15. Yes. A plurality of discharge ports 13 are formed in the flow path wall member 14 at a predetermined pitch, and the recording elements 12 are disposed at positions facing the discharge ports 13. The base 15 is formed by providing the recording element 12 using a photolithography method or the like on a silicon substrate provided with a driving element such as a transistor. The base 15 is provided with a supply port 45 so as to penetrate the silicon substrate, and the liquid supplied from the ink tank is carried to the flow path 46 through the supply port 45. Bubbles are generated by the film boiling of the liquid by the thermal energy generated by the recording element 12, and ink is ejected from the ejection ports 13 by the pressure of the bubbles to perform recording. Further, the recording head substrate 41 is connected to the ink jet recording apparatus via the terminal 17 for electrical connection.

(Control mechanism)
Next, a control configuration for executing recording control of each unit of the ink jet recording apparatus will be described with reference to a block diagram shown in FIG. The interface 25 is used for inputting recorded image data and the like, and sends information to the gate array 29. An MPU (Micro processor unit) 26 performs control and data processing of the sensor controller 36, the heater controller 35, the motor drivers 32 and 33, and the like according to a program stored in the program ROM 27. The dynamic RAM (DRAM) 28 stores various data such as the number of print dots and the number of ink recording head replacements (the recording signal, recording data supplied to the head, etc.) and a table for controlling the fixing heater. Used to do. The gate array 29 controls data transfer among the interface 25, the MPU 26, and the DRAM 28 and transfers print data to a head driver 37 that controls the printhead 1. A carriage motor 31 that controls scanning of the carriage is controlled by a motor driver 32, and the carry motor 30 is controlled by a motor driver 33. The fixing heater 8 is controlled by a heater controller 35, and a temperature sensor 34 for measuring the temperature of the recording medium is controlled by a sensor controller.

  A recording operation using such an ink jet recording apparatus and a fixing method which is a feature of the present invention will be specifically described with reference to the drawings.

(First embodiment)
FIG. 4 is a schematic view illustrating the positional relationship between the image forming area 9 and the fixing heater 8 corresponding to the image data input from the interface. The left end of the image forming area 9 of the recording medium 2 on which recording is performed corresponds to the position of the individual heater 8C, and the right end corresponds to the individual heater 8n. As shown in FIG. 4, in the case where the image forming area 9 is concentrated on only a part of the recording medium 2 without using the entire surface, the recording head of the fixing heater 8 is used to speed up the recording operation. The recording operation is performed by reciprocating scanning in the area corresponding to the individual heater 8C and the individual heater 8n.

  FIG. 5I is an example of a profile showing the set temperature of the individual heater for heating the recording medium so that the beading phenomenon does not occur reliably. The horizontal axis indicates the positional relationship of each individual heater when the individual heater corresponding to the end of the image forming area 9 as shown in FIG. The profile (ii) in FIG. 5 is the temperature of the surface of the recording medium when the heating is controlled with the profile (i). Here, the set temperature of the corresponding individual heater (horizontal axis: 0) in the recording area corresponding to the end of the image forming area 9 where ink is ejected in the return path immediately after ink is ejected in the forward path is at least about 80 ° C. By doing so, it is possible to perform the recording operation without causing the beading phenomenon. Further, the recording area corresponding to the sixth individual heater from the end can perform the recording operation without causing the beading phenomenon by setting the temperature of the corresponding individual heater to at least about 50 ° C. In this way, the set temperature of the individual heater corresponding to the end of the image forming area is set to be higher than the set temperature of the individual heater corresponding to the vicinity of the center of the image forming area. The set temperature is set to decrease as the distance from the end portion increases.

  In the ink jet recording apparatus, a profile set so that the set temperature of the individual heater becomes lower as the distance from the end of the image forming area as shown in FIG. I remember it. A plurality of setting tables corresponding to such individual heaters can be provided corresponding to the recording conditions such as the type of recording medium and the recording environment (temperature and humidity), etc., as appropriate according to the type of recording medium and the recording environment. You can also choose. Furthermore, when the carriage return position is different between the HP side and the BP side (otherwise, when recovery operation such as preliminary ejection is performed only on one side), the time until the next recording scan is performed. Since they are different, separate tables may be prepared on the HP side and the BP side.

  FIG. 6 shows an example of the relationship between the position of the individual heater 8 set using the table of FIG. 5 and the set temperature of the individual heater when the image forming area 9 of FIG. 4 is recorded. The set temperature based on the distance from the HP side of the image forming area is compared with the set temperature based on the distance from the BP side of the image area, and a high temperature is set as the set temperature of the individual heater. The individual heater is not driven outside the image forming area. In FIG. 6, when the individual heater is not driven, the temperature of the individual heater is represented as zero.

  Even when multi-pass printing is performed as described above, the set temperature of the individual heater is determined in accordance with the image forming area 9 by referring to the setting table stored in the storage means, so that the bea The recording operation can be performed without causing a dipping phenomenon. As a result, density unevenness depending on the magnitude of the beading phenomenon can be prevented, and a highly reliable recording operation can be performed. Furthermore, only the area of the recording medium that needs to be heated can be selectively heated, and generation of wrinkles and alteration of the recording medium can be prevented while reducing waste of energy.

  The technology to quickly evaporate and fix the solvent in the ink by heat treatment is a thermoplastic emulsion that is cured and fixed by heating on a vinyl-based recording medium such as vinyl chloride that does not have an ink receiving layer. In particular, it has been attracting attention for applications in which recording is performed using an ink containing. In the case of a vinyl material, if the recording medium is heated too much, wrinkles are generated immediately. Therefore, by controlling the required portion only at a high temperature by referring to the setting table as in the present invention, Even if a special recording medium is used, a good recording operation can be performed.

  Next, the control flow will be described with reference to FIG. FIG. 3 is a flowchart of image formation including the step of determining the set temperature of the fixing heater based on the image data.

  First, in S302, the MPU 26 (image area specifying means) specifies the image forming area 9 on the recording medium from the image data to be recorded on the recording medium. Next, in S303, an individual heater corresponding to the image forming area 9 is specified among the plurality of individual heaters constituting the fixing heater. In subsequent S304, the setting table stored in the storage means is read out. When a plurality of setting tables corresponding to the type of recording medium and the recording environment are stored in the storage means, the setting table corresponding to the recording environment is read out. In S305, referring to the setting table, the temperature of the individual heater corresponding to the distance from the end of the image forming area is read and determined as the set temperature of each individual heater. In S306, the individual heaters are driven so as to reach the set temperature.

  Further, as shown in S307, the temperature on the recording medium is measured by a temperature sensor such as an infrared sensor, and in S308, it is confirmed whether the temperature of the recording medium has reached the target temperature as shown in FIG. The recording scan for performing is started (S309). On the other hand, when the temperature has not reached, the heating by the individual heater is continued. Note that it is preferable to control the temperature so as to reach the target temperature by appropriately measuring the temperature after the recording operation is started. Thereafter, the recording scan and the conveying operation are repeated until the recording of all the image data is completed (S310).

  In addition, from the start to the end of the recording operation, the set temperature of the individual heater is fixed and the temperature is not changed during image recording, so there is no need to provide a heating process again, and the recording operation can be performed without reducing productivity. It can be carried out.

(Second embodiment)
In the first embodiment, an example in which the drive control of the individual heater is performed in consideration of only the image forming area has been shown. However, in the second embodiment, the individual heater is used by using a setting table that also considers the recording duty. An example of drive control is shown. Here, the recording duty is a value indicating the ratio of the number of ejections ejected to the image composition area of the recording medium, and the recording duty of 100% means a case where ejection is performed to all the constituent areas of the pixels of the recording medium. When the recording duty is large, that is, when the number of ejections per unit area of the recording medium is large, the amount of heat required to sufficiently dry the ink droplets becomes larger than when the recording duty is small.

  FIG. 8A is a schematic diagram showing the density of the recording duty for each scan of the recording head based on the image data. The image forming area 9 is formed by 16 recording scans, and is recorded twice. This is an example of completing an image in the same area of the recording medium (two-pass recording). Each recording scan area is divided into a plurality of dot count areas 10 corresponding to individual heaters, and the number of ink droplets (recording duty) corresponding to each dot count area is read from the image data. Here, description will be made using an example where the dot count areas 10a to 10z are divided into 26 portions so as to have the same width as that of the individual heater. For each density, (1) is a recording duty area of 81% or more and 100% or less, (2) is a recording duty area of 61% or more and 80% or less, and (3) is a recording duty area of 41% or more and 60% or less. Region (4) shows a region of recording duty of 21% or more and 40% or less. Further, (5) shows a recording duty area of 0%, that is, an area where ink is not ejected.

  FIG. 8B shows the maximum print duty value extracted from all the print scans (first print scan to 16th print scan) in each of the dot count areas 10a to 10z. The lower graph plots the maximum recording duty value for each dot count area numbered 1 to 26 from the HP side to the BP side. In FIG. 8B, the recording duty of the first and 19th to 26th dot count areas is 0, and the end of the recorded image in the image forming area is the second dot count area on the HP side. It can be seen that on the 10b, BP side, the dot count area is the 18th 10r. The corresponding individual heaters are 8b on the HP side and 8r on the BP side. The center of the recorded image is the 10th 10j of the dot count area, and the corresponding individual heater position corresponds to 8j.

  FIG. 9A shows “the central part from the end of the image forming area on the HP side”, and FIG. 9B shows “the central part from the end of the image forming area on the BP side”. FIG. 6B is a graph obtained by converting the lower diagram of FIG. 5B into the relationship between the position from the end of the image forming area and the recording duty. Here, the horizontal axis is shown in the order of the dot count area, and the edge of the image forming area is 0 in each case.

  FIG. 10 is an example of a table stored in the storage medium in the present embodiment. One table (profile) indicating the relationship between the set temperature of the individual heater and the recording duty is prepared one by one in accordance with the distance from the end of the image forming area. It is configured. Here, the distance is indicated by a dot count area position number. The ink jet recording apparatus stores these setting tables in a storage means such as a DRAM. Furthermore, a plurality of setting tables can be provided corresponding to recording conditions such as the type of recording medium and recording environment (temperature and humidity), and can be selected as appropriate according to the type of recording medium and recording environment. It is sufficient if the number of tables in one recording condition is half of the number of individual heaters, and FIG. 10 shows an example in which one setting table is configured by eight tables. When the carriage return position is different between the HP side and the BP side (otherwise, when recovery operation such as preliminary ejection is performed only on one side), the time until the next recording scan is performed. Therefore, the tables may be prepared separately on the HP side and the BP side.

  The set temperature of the individual heater is set so as to increase at any recording duty from the center (corresponding to the horizontal axis 8 in FIG. 9) to the end (corresponding to the horizontal axis 0 in FIG. 9) of the image forming area. ing. That is, a table is provided so that the heater set temperature increases as the number of ejections per unit area of the recording medium increases when the distance from the edge of the image forming area is constant. Yes. Further, the setting table is such that the set temperature of the individual heater is higher as it is closer to the end of the image forming area. This is because the edge of the image forming area has a short interval between the timing at which ink is ejected in the first recording scan and the timing at which ink is ejected in the next recording scan, and the beading phenomenon is likely to occur. is there. By driving a fixing heater composed of a plurality of individual heaters using such a setting table, the solvent in the ink can be sufficiently volatilized to fix the dye or pigment to the recording medium. The recording operation can be performed without causing a dipping phenomenon. As a result, density unevenness depending on the magnitude of the beading phenomenon can be prevented, and a highly reliable recording operation can be performed.

  Further, when the recording duty is large, that is, as the amount of ejected ink is larger, the amount of heat necessary to sufficiently dry the ink droplets is larger than when the recording duty is small, so that the set temperature of the individual heater is increased. It is a setting table. In addition, by finely controlling the set temperature of the individual heaters as described above, only the area of the recording medium that needs to be heated can be selectively increased in temperature, reducing the waste of energy and changing the quality of the recording medium. Can be prevented.

  FIG. 11 is a graph showing the relationship between the image forming area and recording duty in FIG. 9 and the set temperature of the individual heater determined from the setting table in FIG. Even if the recording duty corresponding to the positions 14 to 18 of the individual heaters is approximately the same, the set temperature of the individual heaters increases toward the image end on the BP side. Although the recording duty corresponding to the positions 4 to 6 of the individual heaters is different, the set temperatures of the individual heaters are almost the same. In addition, the individual heater is not driven outside the image forming area, that is, in an area where the recording duty is 0%. In FIG. 11, when the individual heater is not driven, the temperature of the individual heater is represented as zero.

  Next, the control flow will be described with reference to FIG. FIG. 7 is a flowchart of image formation including the step of determining the set temperature of the fixing heater based on the image data.

  First, in step S <b> 702, the number of ejections is counted for each dot count area 10 divided in the main scanning direction for each recording scan from the image data to be recorded on the recording medium, and the recording duty corresponding to each dot count area 10 is calculated. To do. Next, in S703, the maximum recording duty is extracted in all the recording scans as shown in FIG. 8B in each dot count area 10a-z. Next, the image forming area 9 on the recording medium is specified from the image data on which the recording operation is performed in S704. In step S <b> 705, the individual heater corresponding to the image forming area 9 is specified from the plurality of individual heaters constituting the fixing heater. In step S706, a setting table indicating the relationship between the set temperature of the individual heater and the recording duty in accordance with the distance from the end of the image forming area in FIG. 10 is read from the storage unit. When a plurality of setting tables corresponding to the type of recording medium and the recording environment are stored in the storage means, the setting table corresponding to the recording environment is read out.

  In step S707, the set temperature of each individual heater is determined using the setting table and the maximum recording duty extracted in step S703. In order to calculate the position with the maximum recording duty according to the position from the image forming area, the position from the edge of the image forming area on the HP side as shown in FIG. Converted to a recording duty profile according to. Similarly, after converting to a recording duty profile corresponding to the position from the end of the image forming area on the BP side and clarifying the relationship between the position from the end of the image forming area and the maximum recording duty, refer to the setting table. May be. In S708, the individual heaters are driven so as to reach the set temperature. Since S709 to S712 are the same as S307 to S310 in the first embodiment, description thereof is omitted.

  In addition, from the start to the end of the recording operation, the set temperature of the individual heater is fixed and the temperature is not changed during image recording, so there is no need to provide a heating process again, and the recording operation can be performed without reducing productivity. It can be carried out.

(Third embodiment)
In the second embodiment, an example in which the set temperature of the individual heater is not changed during image recording has been shown. However, in this embodiment, the optimum individual heater set temperature is set for each print scan (that is, every print scan). The control flow in the case of changing and controlling is shown. Since other than that is the same as that of 2nd embodiment, it abbreviate | omits.

In FIG. 12, each recording scan is represented as an nth recording scan (n is a natural number). Before each recording scan, the recording duty corresponding to each dot count area is calculated from the image data corresponding to the recording scan (S1201 to S1203). Next, an individual heater corresponding to the image forming area in the nth recording scan is specified (S1204). Further, a setting table indicating the relationship between the set temperature of the individual heater and the recording duty according to the distance from the edge of the image forming area is read (S1205). Using this setting table and the recording duty in S1203, the set temperature of each individual heater is determined (S1206), and each individual heater is driven (S1207). After confirming whether the recording medium is at a desired temperature (S1208, 1209), the nth recording scan is performed (S1210).
Further, these operations are repeated until the recording scan is completed (S1211).

  As described above, the individual heater is driven so that the temperature setting is optimized for the recording image of the recording scan for each recording scan, thereby suppressing the excess energy and reducing the image quality due to the beading phenomenon. It becomes possible to suppress.

  In the present embodiment, even if there is a portion where no image is recorded in the image forming area, the individual heater corresponding to the corresponding position is not turned off, and is driven to hold, for example, about 50 degrees. Also good. By driving in advance in this way, even if the portion that was not the image forming area in the nth recording scan becomes the image forming area in the (n + 1) th recording scan, the heating time required to reach the recording scanable temperature is reduced. This is because it can be shortened. That is, it is preferable to optimize the stand-by temperature of the individual heater corresponding to the portion where the recording operation is not performed to a temperature that is considered so as not to reduce the productivity as much as possible.

DESCRIPTION OF SYMBOLS 1 Recording head 2 Recording medium 8 Fixing means 9 Image forming area 10 Count area 13 Ejection port 41 Recording head substrate 100 Inkjet recording apparatus 104 Carriage

Claims (11)

A recording head that ejects ink according to input image data;
Scanning means for scanning the recording head in the forward direction and the backward direction along the scanning direction with respect to the recording medium;
Fixing means comprising a plurality of heating means used for heating the recording medium and arranged along the scanning direction;
Control means for driving and controlling each of the plurality of heating means corresponding to the image forming area in order to heat the image forming area of the recording medium,
When the control unit scans the recording head with respect to a unit area on the recording medium a plurality of times to form an image, the set temperature of the corresponding heating unit decreases as the distance from the end of the image forming area increases. As described above, an inkjet recording apparatus that controls driving of the plurality of heating units corresponding to the image forming area of the recording medium. It is a table showing the relationship between the distance from the end of the image forming area and the set temperature of the heating means necessary for fixing the ink at the distance, and the distance from the end of the image forming area increases as the distance from the end increases. And further comprising storage means for storing the table that is set so that the set temperature of the heating means is low,
The control unit refers to the table stored in the storage unit based on the image data when the unit area scans the recording head a plurality of times to form an image. The inkjet recording apparatus according to claim 1, wherein the plurality of heating units corresponding to the image forming area are driven and controlled. The control means specifies an image forming area on the recording medium from the image data, and drives and controls the plurality of heating means with reference to the table based on the specified image forming area. The inkjet recording apparatus according to claim 2. The control means controls the heating so as not to drive the heating means corresponding to the area where the image of the recording medium is not formed when the unit area is scanned with the recording head a plurality of times to form an image. The inkjet recording apparatus according to any one of claims 1 to 3, wherein The ink jet recording apparatus according to claim 1, wherein the ink contains a thermoplastic emulsion. The inkjet recording apparatus according to claim 1, wherein the recording medium is made of vinyl chloride. The inkjet recording apparatus according to claim 1, wherein the recording head includes an electrothermal conversion element for discharging ink. The ink jet recording apparatus according to claim 1, wherein the recording head includes a piezoelectric element for ejecting ink. 9. The fixing device according to claim 1, wherein the fixing unit is provided above the recording medium so that energy can be applied to the recording medium from above the recording medium. The inkjet recording apparatus according to Item. A platen for supporting the recording medium;
9. The fixing device according to claim 1, wherein the fixing unit is provided integrally with the platen so that the recording medium can be heated from below the recording medium. 10. Inkjet recording apparatus. An image is recorded using a recording head that ejects ink based on input image data, and a fixing unit that is used to heat the recording medium and includes a plurality of heating units arranged along the scanning direction. An ink jet recording method comprising:
A scanning step of scanning the recording head in the forward and backward directions along the scanning direction with respect to the recording medium;
A control step of driving and controlling each of the plurality of heating means corresponding to the image forming area in order to heat the image forming area of the recording medium,
In the control step, when the recording head is scanned a plurality of times with respect to the unit area on the recording medium to form an image, the set temperature of the corresponding heating unit decreases as the distance from the end of the image forming area increases. As described above, an ink jet recording method characterized by drivingly controlling a plurality of the heating means corresponding to image forming regions of a recording medium.

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