JP2003291329A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus which restricts color irregularities associated with a heating time variation even when a width of images to be printed or a width of a printing size varies. <P>SOLUTION: The imaging apparatus fixes to a fixing layer of a medium 1 to be recorded, and ink is applied to a surface layer of the medium by transferring the medium with the ink applied to the surface layer with the use of a printing head 2 and passing the medium through a heater 4. The printing head 2 is controlled to drive and discharge ink by printing data formed from image data, and is sent in a main scanning direction. The imaging apparatus is equipped with passing time compensating correcting parts 90 and 91 for correcting to compensate a variation of ink fixing characteristics, because of a variation of a passing time of the medium through the heater when the printing data is formed from the image data. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium having a surface layer to which ink is applied by using a print head which is controlled to eject ink by print data created from image data and is sent in the main scanning direction. The present invention relates to an image forming apparatus that fixes an ink applied to a surface layer to a fixing layer of a recording medium by heating while conveying the ink.

[0002]

2. Description of the Related Art As a printing technique for applying a printing liquid such as ink to a recording medium to obtain a printed matter, for example, a primary image is first formed on a thermal transfer sheet by an ink jet printer or the like, and then a thermal transfer on which the image is formed. By superposing the sheet on the recording sheet and applying pressure and heat, the image (ink) formed on the thermal transfer sheet is thermally sublimated and transferred to the ink fixing layer of the thermal transfer sheet to form a secondary image on the thermal transfer sheet. Then, a thermal transfer technique for obtaining a final printed matter is well known from Japanese Patent Application Laid-Open No. 10-16188. In addition, Japanese Patent Laid-Open No. 10-230589 discloses that
A laminate material layer is provided in advance on the ink fixing layer of the recording sheet, an image is formed on the laminate material layer with an ink jet printer or the like, and then the laminate material layer is made transparent by applying pressure and heat through a heating roller. At the same time, a heat fixing printing technique is disclosed in which a dye of ink is fixed on a fixing layer to obtain a printed matter.

In any case, in such an image forming apparatus, an ink jet head which moves in the main scanning direction while ejecting ink is used, and each time the ink jet head moves in the main scanning direction over the print width, the ink jet head is covered. An image is formed on the recording medium by intermittently conveying the recording medium in the sub-scanning direction (direction orthogonal to the main scanning direction). At this time, the moving distance of the inkjet head in the main scanning direction depends on the width of the image to be printed. That is, if the width of the print size (the length of the print size is taken to be the transport direction of the recording medium) becomes longer, the moving distance also becomes longer, and as a result, the transport speed at which the non-recording medium is transported on the transport line becomes slower. As the width of the print size becomes shorter, the moving distance also becomes shorter, resulting in higher transport speed.

[0004]

As described above, the conveyance speed varies depending on the width of the image to be printed or the width of the print size (generally, the width of the non-recording medium). This brings about a problem that the heating device passage time of the medium varies. In the image forming apparatus as the starting technology of the present invention, considering that the heat fixing property of the ink forming the image has a great influence on the quality of the printed matter as the final product, particularly the occurrence of color unevenness, this problem Cannot be ignored.

In order to solve the problem of fluctuation of the heating time, it is possible to adjust the conveying speed in the heating device according to the width of the image to be printed or the width of the print size. Adjustment will also affect other transfer lines, and the configuration and control of the transfer device will be complicated, which will be a major factor in cost increase. Further, it is possible to adjust the heating temperature in the heating device according to the width of the image to be printed or the width of the print size. However, the adjustment of the heating temperature involves a delay time, and the print size that frequently occurs is adjusted. There is a problem that changes cannot be dealt with quickly. In view of the above situation, an object of the present invention is to provide an image forming apparatus in which even if the width of an image to be printed or the width of a print size changes, the occurrence of color unevenness due to a heating time change is suppressed. is there.

[0006]

In order to solve the above-mentioned problems, a print head whose ink ejection drive is controlled by print data created from image data and which is sent in the main scanning direction is used to print ink on its surface layer. An image forming apparatus for fixing an ink applied to a surface layer to a fixing layer of a recording medium by heating the applied recording medium while conveying the same, in the present invention, a heating device for heating the recording medium. A transport mechanism for transporting the recording medium to which ink has been applied so as to pass through the heating device, and ink fixing due to fluctuations in the transit time of the recording medium in the heating device when creating print data from the image data. A transit time compensation correction unit that performs correction for compensating for characteristic fluctuations is provided.

According to the knowledge of the inventor of the present invention, since the moving distance of the ink jet head in the main scanning direction becomes long during printing, it takes time to convey the total non-recording medium,
As a result, when the recording medium passes through the heating device for a long time, the sublimation fixing of the ink by heating proceeds more than a predetermined amount,
The density value of each dot formed by the ejected ink droplets tends to be higher than the desired value, and on the contrary, the movement distance of the inkjet head in the main scanning direction is shortened, and the total non-recording medium conveyance is short. As a result, when the time taken for the recording medium to pass through the heating device is shortened, the sublimation fixing of the ink due to heating becomes insufficient than a predetermined value, and the density value of each dot formed by the ejected ink droplet tends to be lower than the desired value. There is.

In the structure according to the present invention, the density value belonging to each pixel forming the image data is adjusted according to the variation of the passage time of the recording medium in the heating device, and each density in the finally obtained recording medium is adjusted. The dot density value is set to a desired value. In other words, when the recording medium passage time in the heating device becomes longer than a predetermined value, the density value belonging to each pixel forming the image data is lowered, and when the recording medium passage time in the heating device becomes shorter than the predetermined value, the image data Increase the density value belonging to each pixel constituting the. As a result, even if the width of the image to be printed or the width of the print size is changed and the heating time for the recording medium is shortened or shortened, the density of the image data that is the source of the printing can be adjusted and changed in advance. The occurrence of color unevenness is suppressed.

The size of the image data to be printed is first mentioned as one of the specific examples for recognizing the fluctuation of the moving time of the ink jet head in the main scanning direction. Since the width of the image to be printed is easily calculated from the image data as the print source, a correction table depending on the size of the image data to be printed is created in advance, and the transit time compensation correction unit is used to calculate the calculated print. The transit time compensation correction may be performed by using a suitable correction table designated based on the width of the image. Usually, in such an image forming apparatus, image data is converted according to a desired print image size (also simply referred to as print size), and an image according to the print size is formed. Therefore, the print size set by the operator can be employed as another specific example for recognizing the fluctuation of the movement time of the inkjet head in the main scanning direction.
In that case, a correction table is created in advance for each heating device passage time that depends on the print size, and the passage time compensation correction unit uses the appropriate correction table specified based on the set print size to set the passage time. Compensation correction should be performed.

Further, since the recording medium to be used is usually determined according to the print size, it is mounted as another example of the concrete example for recognizing the fluctuation of the moving time of the ink jet head in the main scanning direction. It is also possible to use the type of non-recording medium that is present, that is, its width. In that case, a correction table is created in advance for each heating device passage time depending on the type (width) of the non-recording medium, and the passage time compensation correction unit is designated based on the type of the attached non-recording medium. A transit time compensation correction can be performed using a suitable correction table.

In a preferred embodiment of the present invention, a temperature detector for detecting the heating temperature of the heating device is provided, and the heating temperature in the heating device is corrected by the passage time compensation corrector. Taken into account when selecting a table. When handling a wide range of print image widths, it is difficult to compensate for the final difference in print dot density due to the length of the passage time only by the difference in the density value of the image data. For this reason, the print image width is divided into a plurality of areas, and the standard heating temperature is set in each area.
It is also preferable to compensate for the difference in the transit time within the area by correcting the image data by the transit time compensation corrector. That is, the excess or deficiency of the heating energy for the non-recording medium caused by the difference in the print image width is compensated by both the adjustment of the heating temperature and the correction of the image data.

In another one of the preferred embodiments of the present invention,
A mode selection unit is provided that selectively switches between a passage time compensation mode in which the image data is corrected by the passage time compensation and correction unit and a passage time non-compensation mode in which this correction is not performed. When a recording medium of a type that does not require heat fixing is selected, the passage time compensation is not necessary. Providing a mode selection function for selecting a transit time compensation mode and a transit time non-compensation mode in which this correction is not performed for such a case enhances the versatility of this image forming apparatus. Other features and advantages of the present invention will become apparent from the following description of the embodiments with reference to the drawings.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an example of a recording medium 1 handled by an image forming apparatus according to the present invention will be described with reference to FIG. The recording medium 1 is a fixing layer 11 for ink, that is, dye, made of urethane resin or the like on the surface of a substrate 10 made of a film sheet such as PET (polyethylene terephthalate).
And a surface layer 12 as a penetrating layer capable of penetrating ink. Substrate 1
When the surface of No. 0 has a property of being able to fix the dye, the fixing layer 11 can be omitted. When an image is formed by applying ink droplets to the surface layer 12 of the recording medium 1 with an inkjet printer or the like, and then heated to an appropriate temperature, the applied ink droplets penetrate the surface layer and the fixing layer 11 is formed. Then the dye is fixed. Further, by peeling off the surface layer 12, a vivid image-recorded sheet having a very glossy feeling is obtained as the final printed matter 100.
In this recording medium 1, the surface layer 12 is finally provided with the fixing layer 11
Alternatively, since it is necessary to peel it from the substrate 10, it is convenient to provide an easy peeling agent between them.

An example of an image forming apparatus for producing the final printed matter 100 using the recording medium 1 will be described with reference to FIGS. 2 and 3. As shown in FIG. 2, this image forming apparatus is composed of a print station PS and an operating station OS.

The print station PS is composed of an ink jet print unit IU, a heat fixing unit HU mounted on the paper discharge side of the ink jet print unit IU, and a housing for covering them.

As is apparent from FIG. 3, in the print station PS, the recording medium 1 wound in a roll shape, which is housed in a roll sheet cartridge (not shown), is rewound and its surface, which is the print surface, is rewound. The recording medium 1 is conveyed by the sheet conveying mechanism 6 so that the layer 12 is located on the ink ejection port side of the inkjet head 2 as a print head. The inkjet head 2 is supported by a head feed mechanism 3 so as to be capable of reciprocating in a direction transverse to the transport direction of the recording medium 1, that is, in the main scanning direction. Each time the inkjet head 2 moves in the main scanning direction while ejecting, the recording medium 1 is conveyed in the sub scanning direction, so that print images are sequentially formed. The inkjet head 2 is provided with a plurality of ejection port modules capable of ejecting different main colors to form a color print image. For example, when a color print image of photographic quality is required, dark and light inks of the same color are usually used in addition to inks of cyan, magenta, yellow, black and the like. As the inkjet head 2, the one mounted on a general-purpose inkjet printer is diverted, so that further description is omitted here.

The recording medium 1 having a print image formed on the surface layer 12 by the ink droplets 2a ejected from the ink jet head 2 is an ink jet print unit I.
After passing through U, the ink is sent to the heat fixing unit HU forming a heat fixing area where heat fixing of the ink to the fixing layer 11 is performed. The heating and fixing unit HU is equipped with a heating device 4.

In the recording medium 1 that has passed through the heat fixing area, the ink (dye) forming the print image is fixed on the fixing layer 11, so that the surface layer 12 is peeled off to develop a clear color. The final print 100 with the image is obtained. Although a series of conveyances of the recording medium 1 are performed by the conveyance mechanism 6 shown here as a roller method, other conveyance methods such as a belt method may be adopted.

Recording medium 1 which is originally a long sheet
The sheet cutter means 5 is provided because it is necessary to cut the sheet according to the size of the print image formed thereon. In this embodiment, the sheet cutter means 5 includes a first sheet cutter 5A attached to the inkjet head 2 and a second sheet cutter 5B provided in a region on the rear side in the transport direction of the heating device 4. Since the blade 51 of the first sheet cutter 5A is attached to the inkjet head 2, the recording medium 1 can be cut by driving the head feeding mechanism 3, whereas the blade of the second sheet cutter 5B is cut. A dedicated feeding mechanism 53 for reciprocating the 52 is provided.

Therefore, when a plurality of print images are continuously formed, the recording medium 1 is cut by the first sheet cutter 5A at the rear end of the entire length thereof, and each print image unit is cut first. 2 Sheet cutter 5B
When forming a single print image, the recording medium 1 is cut into a print image size by the first sheet cutter 5A and sent to the heating device 4.

The heating device 4 has an electric heater 41 for increasing the temperature of air in the heating space formed by a wall 40 made of a heat insulating material and a temperature for measuring the temperature in the heating space. A fan 43 that sends heated air heated by the sensor 42 and the electric heater 41, a fan motor 44 that drives the fan 43, and a shield plate 45 that prevents the heat from the electric heater 41 from being directly applied to the recording medium. Is equipped with. By contacting the recording medium 1 with air heated to a predetermined temperature inside the heating space, non-contact heating is performed on the recording medium 1 and sublimation fixing of ink by this heating is realized. In order for the recording medium 1 to pass through the heating space, the transport mechanism 6 is provided with a pressure-type transport roller unit including a driving roller and a driven roller at positions sandwiching the heating space.

In this embodiment, the heating device 4 is configured to heat the recording medium 1 with heated air, but instead of this, an infrared heater (including a far infrared heater) is provided inside the heating space. Alternatively, the recording medium 1 may be heated by a radiant heat beam of infrared rays.

In the recording medium 1 described above, the sublimable ink used in this embodiment starts sublimation at about 80 ° C., and reaches an optimum sublimation fixing state by heating at 180 ° C. for about 2 minutes. In addition, this sublimation ink is 170 ° C.
Sublimation of the ink is reasonably performed at about 200 ° C.

However, the recording medium 1 passing through the area of the inkjet head 2 while the image is formed on the surface layer 12 by the ejected ink is intermittently transported, but the average transportation speed is reciprocating in the main scanning direction of the inkjet head 2. The moving time depends on the print image width. For example, as shown in FIG. 4, the print image width 1
At 00 cm, the average transport speed is about 10 cm / min, and at a print image width of 20 cm, the average transport speed is about 40 cm / min. Such fluctuations in the average transport speed cause fluctuations in the time taken for the recording medium 1 to pass through the heating device 4, resulting in a large difference in the heat fixing process, resulting in variations in the ink fixing characteristics obtained in each case.

To solve this problem, it is conceivable to change the heating temperature in the heating device 4 according to the average transport speed so that the thermal energy applied to the recording medium 1 becomes almost constant. It is difficult to accurately control the heating temperature over a wide temperature range. In some cases, printing may have to wait until the desired temperature is reached. Therefore, in the present invention, the print image width handled by the image forming apparatus is divided into a predetermined range, and in this embodiment, the first width area: B1, the second width area: B2, the third width area: B3, and the fourth width area. Width area: Divided into 4 areas of B4, and appropriate heating temperature: T1, T2, T
3, T4 is allocated. The difference in the ink fixing characteristics caused by the difference in the average transport speed in each width region is due to the correction of what is referred to as the transit time compensation correction for the density value of each pixel forming the image data as the print source. By doing so, the density value of each dot of the finally obtained print image is set to a desired value. For example, if the average transport speed is faster than the standard, sufficient heating and, as a result, sufficient sublimation fixing cannot be obtained, and the density of the final print dots tends to be low, the density value of the image data is listed in advance. Keep it. When the print image width handled by the image forming apparatus is narrow, it is possible to keep the heating temperature constant and correct only the image data.

The ink jet head 2, the head feed mechanism 3, the heating device 4, the sheet cutter means 5, the transport mechanism 6 and the like are comprehensively controlled by a controller 7. A sheet detection sensor 60 is installed at a predetermined position of a conveyance line formed by the conveyance mechanism 6 to grasp the position of the recording medium 1 conveyed by the conveyance mechanism 6, and a detection signal thereof is also sent to the controller 7. Further, a recording medium type detection sensor 61 for detecting an ID code given to the shaft body that winds and supports the roll sheet cartridge or the recording medium 1 is also installed to send the detection signal to the controller 7. From this detection signal, the controller 7 can recognize the specifications of the loaded recording medium 1, for example, the length in the direction perpendicular to the transport direction, that is, the recording medium width.

The controller 7 of this image forming apparatus is composed of a first controller 7A on the operating station OS side and a second controller 7B on the print station PS side, which are connected to each other via a communication cable so that data can be exchanged. It can function like a controller.

As shown in FIG. 2, the operating station OS includes a general-purpose computer 80 that also functions as the first controller 7A, a monitor 81, a keyboard 82, a mouse 83, and a developed silver-salt film. A film scanner 85 for photoelectrically converting a captured image of F into color image data, and further a data holding medium (CD
The image acquisition unit 84 (here, not only a semiconductor medium such as CompactFlash (registered trademark) or smart media, but also a communication medium including a data communication line) for extracting color image data from the CD, the CD-R, the MO, the MO, or the like. Is built into the computer 80). In this image forming apparatus, the color image data transferred to the first controller 7A through the film scanner 85 and the image acquisition unit 84 is
After various data processing is performed, it is sent to the second controller 7B as print data, and a print image is formed on the recording medium 1 at the print station PS.

The controller 7 includes a CPU, ROM, RA
It is composed of a first controller 7A and a second controller 7B whose core members are a microcomputer system including M and I / O interface circuits.
In the first controller 7A, as shown in FIG.
Peripheral devices such as an image acquisition unit 84 for sending image data and a film scanner 85 are connected via an interface circuit. In the second controller 7B, I
Peripheral devices incorporated in the print station PS, such as the inkjet head 2, the head feed mechanism 3, the heating device 4, and the transport mechanism 6, are connected via the / O interface circuit. The first controller 7A and the second controller 7B are capable of data transmission via their respective communication modules, and are substantially the first controller 7A.
The image data that has been subjected to the image processing and the correction processing in is converted into the final print data, and the communication module 74
After being transmitted to the second controller 7B via a and 74b, it is used for applying sublimable ink to the recording medium 1.

Each function of the controller 7 is created by hardware and / or software, and here, if only the functional elements relating to the present invention are taken into consideration, it is designated through the operation of the keyboard 82 or the mouse 83 by the operator. An image on which the resolution is changed or trimmed based on the print image size set by the print size setting unit 70 for the image data transferred from the image size input unit 9 The processing unit 72 is used in the correction unit 90 and the correction unit 90 that perform the above-described correction processing for the transit time compensation that characterizes the present invention in addition to general image correction processing such as color correction and head shading correction. A correction table storage unit 92 for storing the correction table 91 is required. Correction mode selection unit 9 to load the correction unit 90 from the correction table storage unit 92 to the correction table 91 as well as specifying a particular correction table 91
3. A print data generation unit 73 that generates print data for the inkjet head 2 from the corrected image data by using a binarization method such as error diffusion; and the inkjet head 2 based on the transferred print data.
A print control unit 75 for driving the inkjet head 2 to discharge ink droplets from the ejection port, a head feed control unit 76 for moving the inkjet head 2 in the main scanning direction at the same time as driving the inkjet head 2, and one in the main scanning direction of the inkjet head 2.
The infrared heater 41 of the heating device 4 is drive-controlled based on the detection signal from the conveyance controller 77 and the temperature sensor 42, which feeds the recording medium 1 to the heating device 4 intermittently at every movement. Typical examples are a heating control unit 78 and a recording medium type determining unit 79 that acquires information such as the width of the loaded recording medium 1 from the ID code read by the recording medium type detection sensor 61. .

The heating control unit 78 sets a heating temperature obtained by applying the print image size set by the print size setting unit 70 to the relationship between the print image width and the heating temperature shown in FIG. The heating temperature setting unit 78a is included. The heating control unit 78 controls the electric heater 41 and the fan 43 to bring the temperature of the heating space to the set heating temperature.

Next, how a photographed image is formed on the recording medium 1 using the color image data of the photographed image read from the color negative film F by the film scanner 85 will be described with reference to the schematic flow chart of FIG. To do.

When the color negative film F is read by the film scanner 85, CC of the film scanner 85 is read.
The output signal of D is amplified and AD-converted to 12-bit RG.
It is transferred to the image data input unit 71 as B color image data (# 01). The color image data is subjected to typical correction such as gamma correction as scanner data in the image data input unit 71, and then sent to the image processing unit 72 (# 0
2). Around this time, the operator operates the keyboard 82 and the mouse 83 while looking at the print order slip, designates and inputs the print image size, and sets the print image size in the print size setting unit 70 (# 03).

The image processing section 72 performs resolution conversion corresponding to the finished print size based on the (# 04) print image size received from the print size setting section 70 for the sent color image data, and if necessary. Is trimmed and 12-bit data is converted to 8-bit data and passed to the correction unit 90 (# 05).

In the correction section 90, in addition to the color correction processing that is normally performed in digital photographic printing, in order to compensate for variations in ink fixing characteristics due to the length of time that the recording medium 1 passes through the heating space of the heating device 4. Passage time compensation correction processing is performed. The correction ratio used for this transit time compensation correction processing is prepared for each print image width defined in FIG. 4, and is selected by the correction mode selection unit 93. The print image width for the print size setting unit 7
It is fetched from 0 to the correction mode selection unit 93 (# 0
6). The correction ratios related to various corrections are managed in the form of a correction table (lookup table) 91. Therefore, when performing various correction processes, the correction mode selection unit 93 specifies the address (# 07) in the correction table storage unit 9
The correction table 91 (# 08) loaded from 2 to the correction unit 90 is used.

Since the correction table for image processing which is generally used is well known, only the correction table 91 for passing time compensation will be described here. As is clear from FIG. 4, the average transport speed fluctuates to some extent even in each width area B1 to B2 divided from the print image width, and as a result, the passing time through the heating space is shortened and shortened. The density of the printed dots that are printed will vary. Therefore, it is necessary to compare the measured density value and the target density value of the print dots obtained by performing the print test with various print image widths selected from the print image width area in advance, and to compensate for the difference. The correction amount of the density value in the image data is determined. The determined correction amount is stored in the correction table storage unit 92 in the form of the correction table 91. The correction table 91 created and stored in this way is a transit time compensation correction table. That is, when the correction table for the passage time compensation is designated by the correction mode selection unit 93 and loaded into the correction unit 90, the correction unit 90 functions as the passage time compensation correction unit. Of course, in the case where a normal inkjet recording paper that does not need to be heat-fixed is used as the recording medium 1, the passage time compensation correction is omitted by the correction mode selection unit 93 that can be operated by the operator using the keyboard 82 or the like. To be done.

When all necessary color image data corrections are completed in the correction section 90, this color image data is sent to the print data generation section 73 (# 9). In addition, R
Since the GB color image data has been converted into CMYK color image data by the correction unit 90 at an appropriate stage before and after other corrections, the color image data sent to the print data generation unit 73 is CMYK color image data.

The print data generator 73 receives 8
2 for performing gradation formation by area gradation by the inkjet head 2 from CMYK color image data of bits
Binarization CMYK print data is created by performing the binarization process, and is transferred to the print controller 75 (# 10).

The print control unit 75 generates a drive pulse signal for the ink jet head 2 from the transferred binary CMYK print data, and thereby controls the drive element of the ink jet head 2 to ink the recording medium 1. Spray drops. At the same time, the head feed control unit 75 drives and controls the head feed mechanism 3, and the transport control mechanism 77 drives and controls the transport mechanism, so that a captured image is formed on the recording medium 1 (# 11).

The heating temperature setting section 78a in the heating control section 78 sets a predetermined heating temperature from the print image width sent from the print size setting section 70, and the heating control section uses the set heating temperature as a control target temperature. 78 adjusts the temperature of the heating space of the heating device 4 (# 12). The recording medium 1 on which the photographed image is formed is heated and fixed by passing through a heating space whose temperature is appropriately adjusted at a transport speed corresponding to the transport speed in the area of the print jet head 2. Even if the actual transport speed deviates from the standard transport speed, the density value of the image data is corrected to compensate for it, so that the final printed matter 100 having the desired color tone is finally obtained. .

In the above-described embodiment, the print image size is adopted as a factor of the passage time variation of the recording medium 1 in the heating device, which causes the variation of the ink fixing characteristic. However, instead of this, the recording medium type determining unit is used. The width (length in the direction orthogonal to the transport direction) of the recording medium 1 obtained from 79 may be adopted. Normally, the recording medium 1 is selected according to the ordered print image size, so that the average transport speed is substantially determined from the type of the recording medium 1 loaded. It is possible to select an appropriate transit time compensation correction table 91 from the type of the recording medium 1. It is also possible to calculate the print image size from the size of the image data as the print source instead of the information from the print size setting unit 70.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a recording medium handled by an image forming apparatus according to the present invention.

FIG. 2 is an external view showing an embodiment of an image forming apparatus according to the present invention.

FIG. 3 is a schematic sectional view showing the configuration of a print station of the image forming apparatus.

FIG. 4 is a graph showing a relationship between a print image width and an average conveyance speed of a recording medium.

FIG. 5 is a functional block diagram illustrating the functions of the controller.

FIG. 6 is a schematic flow chart showing a state in which input image data is corrected and then sent as print data to an inkjet head to form an image on a recording medium.

[Explanation of symbols]

1 Recording medium 2 inkjet head 3 head feeding mechanism 4 heating device 6 Transport mechanism 7 controller 7A 1st controller 7B Second controller 42 Temperature sensor 72 Image processing unit 73 Print data generator 75 Print control unit 90 Correction unit (Transmission time compensation correction unit) 91 Correction table (Transmission time compensation correction table) 92 Correction table storage unit 93 Correction mode selection section

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masazumi Ishikawa             No. 1 at 579 Umehara, Wakayama City, Wakayama Prefecture             Inside Ritsu Koki Co., Ltd. F-term (reference) 2C056 EA06 EB14 EB30 EC12 EC14                       EC21 EC79 HA44                 2C058 AB17 AC07 AC11 AD01 AE02                       AF15 GA09 GE24

Claims (6)

[Claims] 1. A recording medium, whose surface layer is provided with ink, is heated while being conveyed by using a print head whose ink ejection drive is controlled by print data created from image data and which is sent in the main scanning direction. In the image forming apparatus for fixing the ink applied to the surface layer to the fixing layer of the recording medium, the heating device for heating the recording medium and the recording medium applied with the ink pass through the heating device. A transport mechanism for transporting the image data to the recording medium, and a passage time compensation correction unit that performs correction for compensating for variations in ink fixing characteristics due to variations in transit time of the recording medium in the heating device when creating print data from the image data. An image forming apparatus comprising: 2. The transit time compensation corrector corrects the image data using a correction table preset based on image data to be printed, which causes fluctuations in the transit time of the recording medium in the heating device. The image forming apparatus according to claim 1, wherein: 3. The passage time compensation correction unit corrects the image data by using a correction table preset based on the width of the recording medium used, which causes variation in the passage time of the recording medium in the heating device. The image forming apparatus according to claim 1, wherein: 4. The passage time compensation correction unit corrects the image data by using a correction table preset based on a print image size which causes a variation in the passage time of the recording medium in the heating device. The image forming apparatus according to claim 1. 5. A temperature detection unit for detecting a heating temperature of the heating device is provided, and the heating temperature of the heating device is considered when selecting a correction table used in the transit time compensation correction unit. The image forming apparatus according to any one of claims 1 to 4. 6. A mode selection unit is provided for selectively switching between a passage time compensation mode in which the image data is corrected by the passage time compensation correction unit and a passage time non-compensation mode in which the correction is not performed. The image forming apparatus according to any one of claims 1 to 5, which is characterized.