JP4289538B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the present invention, the ink applied to the surface layer is heated by heating a recording medium to which the ink is applied to the surface layer using a print head that is driven and controlled by print data created from image data. The present invention relates to an image forming apparatus that performs sublimation fixing on a fixing layer of a recording medium.
[0002]
[Prior art]
As a printing technique for applying a recording medium to a printing liquid such as ink to obtain a printed material, for example, a primary image is first formed on a thermal transfer sheet by an inkjet printer or the like, and then the thermal transfer sheet on which the image is formed is recorded on the recording sheet The image (ink) formed on the thermal transfer sheet is subjected to thermal sublimation transfer to the ink fixing layer of the thermal transfer sheet to form a secondary image on the thermal transfer sheet. A thermal transfer technique for obtaining a printed material is well known from JP-A-10-16188.
In JP-A-10-230589, a laminate material layer is provided in advance on an ink fixing layer of a recording sheet, an image is formed on the laminate material layer with an ink jet printer or the like, and then pressed through a heating roller. A heat fixing printing technique is disclosed in which a laminate material layer is made transparent by heating and an ink pigment is fixed to a fixing layer to obtain a printed matter.
[0003]
[Problems to be solved by the invention]
In such an image forming apparatus, generally, an image formed of ink droplets (herein referred to as pre-sublimation print dots) by ejecting sublimable ink onto a recording medium conveyed in the sub-scanning direction. In the heat-fixing process, the ink droplets are further sublimated by heating to fix the sublimation ink dye (referred to as print dots after sublimation here) on the fixing layer of the recording medium. A final image consisting of the printed dots after sublimation is obtained.
[0004]
For this reason, the sublimation fixing characteristics of the ink to the fixing layer in the heating sublimation fixing process are very important because they greatly affect the quality of the printed matter as the final product. This sublimation fixing characteristic depends on the type of ink to be used, the type of recording medium and the difference in heating sublimation method, etc., but according to the typical sublimation fixing characteristic based on the knowledge of the present applicant, the heating sublimation fixing process When the heating of the recording medium by the heating device is insufficient with respect to the heating time and / or the heating temperature, high sharpness is obtained in the final image (printed dots after sublimation), but the density tends to be low. If it is excessive, a high concentration can be obtained, but its sharpness tends to be low. This creates a sharp post-sublimation print dot that is insufficiently concentrated but causes insufficient sublimation of the ink droplets, but does not diffuse, and overheated that results in sublimation of the ink droplets too much blur due to large diffusion. However, it seems to produce post-sublimation printed dots with a high density, that is, a wide density dynamic range.
[0005]
Because of such conflicting characteristics regarding sharpness and density dynamic range, first, as a compromise, the heating device is controlled so that the recording medium is heated (with respect to the heating time and / or the heating temperature), which is an intermediate characteristic between the two. However, depending on the image to be printed, it is often the case that only sharpness or density dynamic range is given priority, and such a compromise always results in satisfying many print users. It will not be. In view of the above circumstances, the problem of the present invention is that the image forming apparatus of the type described at the beginning is a starting technology, and the sharpness and density dynamic range depending on the heating behavior of the recording medium that occurs in the heating and sublimation fixing process conflict. An object of the present invention is to provide an image forming apparatus that solves the problem of characteristics.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, a recording medium having ink applied to the surface layer is heated by a heating device using a print head that is driven and controlled by print data created from image data. In the image forming apparatus for sublimating and fixing the ink to the fixing layer of the recording medium, the present invention controls the heating behavior of the recording medium to determine the sublimation fixing characteristics from the surface layer of the ink to the fixing layer. The heating control unit includes a high sharpness control mode that prioritizes sharpness over the density dynamic range by making heating to the recording medium insufficient, and sharpness by making heating to the recording medium excessive. Wide density dynamic range control mode that prioritizes density dynamic range And a control data management unit for each heating control mode that creates a relationship table between the heating temperature and heating time and the sharpness zone and dynamic range zone from the density value of the test chart of the test print created by heating with the heating device. The heating control unit includes a heating control mode setting unit that receives the target heating temperature and / or the target heating time output from the control data management unit for each heating control mode and performs temperature control. .
[0007]
In this configuration, when high sharpness is required even at the expense of density dynamic range characteristics, the heating control unit operates in the high sharpness control mode, and the heating behavior of the recording medium by the heating device indicates the pre-sublimation print dots. The heating control unit operates in the wide density dynamic range control mode when it does not sublimate too much and requires a wide density dynamic range at the expense of sharpness characteristics, and the heating behavior of the recording medium by the heating device The pre-sublimation printed dots are sufficiently sublimated. As a result, printing that gives priority to one of the sharpness and density dynamic range determined by the image to be printed or at the request of the print user can be performed only by switching the control mode of the heating control unit.
[0008]
The priority of either the sharpness characteristic or the density dynamic range characteristic is not clearly determined by the image to be printed or by the print user's desire, but often depends on a rather delicate feeling. For this reason, the fact that the heating behavior between the high sharpness control mode and the wide density dynamic range control mode can be adjusted stepwise or steplessly increases the versatility of the image forming apparatus. At this time, when this image forming apparatus is used in a pro shop, it is advantageous to be able to adjust steplessly with an emphasis on the skill level of the operator, and conversely a general print When handled by an inexperienced operator in a shop, it is advantageous to be configured to be adjustable in stages. Of course, you may employ | adopt the structure which enables both stepwise adjustment and stepless adjustment.
[0009]
One specific example of the above-described heating behavior control for the recording medium by the heating device is adjustment of the heating temperature for the recording medium in the heating device. By setting the heating temperature of the heating device high, sublimation of the printed dots before sublimation is strongly promoted, and after printing the sublimation of very high density can be obtained, and the heating temperature of the heating device should be set low. Thus, sublimation of the print dot before sublimation is suppressed, and a sharp post-sublimation print dot without diffusion can be obtained even if the density does not increase sufficiently.
[0010]
Another specific example of the heating behavior control for the recording medium by the heating device is adjustment of the heating time for the recording medium in the heating device. For example, the heating time of the recording medium can be adjusted by adjusting the staying time of the recording medium in the heating device. By setting the staying time of the recording medium in the heating device to be long, the sublimation of the print dots before sublimation is strongly promoted, and a very high density post-sublimation print dot can be obtained. By setting the stay time of the recording medium to be short, sublimation of the print dots before sublimation is suppressed, and sharp post-sublimation print dots that do not diffuse even if the density does not increase sufficiently can be obtained.
[0011]
Of course, as a specific example of the heating behavior control for the recording medium by the heating device, adjusting both the heating temperature and the heating time for the recording medium in the heating device cannot be excluded. This is because the degree of sublimation can be adjusted in a wider range by combining these two. Adjusting both the heating temperature and the heating time means adjusting the thermal energy applied to the recording medium. From this viewpoint, for example, in the case of a heating device using a heating flow fan, the heating flow fan Adjustment of the amount of heated airflow can also be mentioned as one of the heating behavior controls of the present invention.
Other features and advantages of the present invention will become apparent from the following description of embodiments using the drawings.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
First, an example of a recording medium 1 handled by the image forming apparatus according to the present invention will be described with reference to FIG. In this recording medium 1, a fixing layer 11 for ink, that is, an ink coloring matter is formed on a surface of a base material 10 made of a film sheet such as PET (polyethylene terephthalate) with urethane resin, and the ink is further permeated thereon. The surface layer 12 is formed as an osmotic layer capable of forming When the surface of the substrate 10 has a property capable of fixing the ink pigment, the fixing layer 11 can be omitted. After a print image with pre-sublimation print dots was formed by applying ink droplets to the surface layer 12 of the recording medium 1 with an ink jet printer or the like, it was applied to the surface layer 12 when heated to an appropriate temperature. Ink droplets (printed dots before sublimation) start sublimation, the ink droplets penetrate the surface layer 12, and the ink coloring matter is sublimated and fixed on the fixing layer 11 as printed dots after sublimation. Therefore, by peeling off the surface layer 12, a very glossy and vivid image-recorded sheet having a print image formed by post-sublimation print dots on the fixing layer 11 is obtained as the final printed matter 100. That is, in this heating sublimation process, the ink pigment applied to the surface layer 12 as the pre-sublimation print dots penetrates the surface layer 12 and reaches the fixing layer 11, where a print image is formed as the post-sublimation print dots. In this recording medium 1, since it is necessary to finally peel off the surface layer 12 from the fixing layer 11 or the base material 10, it is convenient to provide an easy-release agent between them.
[0013]
An example of an image forming apparatus for producing the final printed matter 100 using such a recording medium 1 will be described with reference to FIGS. As shown in FIG. 2, the image forming apparatus includes a print station PS and an operating station OS.
[0014]
The print station PS includes an inkjet print unit IU, a heat fixing unit HU mounted on the paper discharge side of the inkjet print unit IU, and a housing that covers these units.
[0015]
As apparent from FIG. 3, in the print station PS, the surface layer 12 that is the print surface is formed while the recording medium 1 wound in a roll shape stored in a roll sheet cartridge (not shown) is rewound. The recording medium 1 is transported by the sheet transport mechanism 6 so as to come to the ink discharge port side of the ink jet head 2 as a print head. The inkjet head 2 is supported so as to be reciprocally movable by a head feeding mechanism 3 in a direction transverse to the conveyance direction of the recording medium 1, that is, in the main scanning direction. Each time the ink-jet head 2 is moved in the main scanning direction while being ejected, the recording medium 1 is conveyed in the sub-scanning direction, whereby print images are sequentially formed. A plurality of discharge port modules capable of discharging different main colors to form a color print image are prepared in the inkjet head 2. For example, when a photographic quality color print image is required, in general, dark and light inks of the same color are used in addition to inks such as cyan, magenta, yellow, and black. Since the inkjet head 2 mounted on a general-purpose inkjet printer is used, further explanation is omitted here.
[0016]
The recording medium 1 on which the print image is formed on the surface layer 12 by the ink droplets 2a ejected from the ink-jet head 2 passes through the ink-jet print unit IU and creates a heat-fixing region in which the heat-fixing of the ink to the fixing layer 11 is performed. To the heating and fixing unit HU. The heat fixing unit HU is provided with a heating device 4.
[0017]
In the recording medium 1 that has passed through the heat fixing region, the ink (pigment) forming the print image is fixed on the fixing layer 11, so that the surface layer 12 is peeled off to have an image that is clearly colored. A final printed product 100 is obtained. Although a series of conveyance of the recording medium 1 is performed by the conveyance mechanism 6 shown here by a roller method, other conveyance methods such as a belt method may be adopted.
[0018]
Since the recording medium 1 that is originally a long sheet needs to be cut according to the size of a print image formed thereon, a sheet cutter means 5 is provided. In this embodiment, the sheet cutter means 5 includes a first sheet cutter 5 </ b> A attached to the inkjet head 2 and a second sheet cutter 5 </ b> B provided in a rear region in the conveying direction of the heating device 4. The first sheet cutter 5A can cut the recording medium 1 by driving the head feed mechanism 3 because the blade 51 is attached to the inkjet head 2, whereas the second sheet cutter 5B has the blade A dedicated feeding mechanism 53 for reciprocating the 52 is provided.
[0019]
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, and each print image unit is cut by the second sheet cutter. When a single print image is formed at 5B, the recording medium 1 is cut into a print image size by the first sheet cutter 5A and sent to the heating device 4.
[0020]
The heating device 4 includes an electric heater 41 for increasing the air temperature in the heating space, and a temperature sensor 42 for measuring the temperature in the heating space, in the heating space formed by the wall 40 made of heat insulating material. A fan 43 for sending heated air heated by the electric heater 41, a fan motor 44 for driving the fan 43, and a shielding plate 45 for preventing a phenomenon in which heat from the electric heater 41 is directly irradiated onto the recording medium are provided. Yes. 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 ink sublimation fixing is realized by this heating. In order for the recording medium 1 to pass through the heating space, the transport mechanism 6 is provided with a pressure-feed type transport roller unit composed of a driving roller and a driven roller at a position sandwiching the heating space.
[0021]
In this embodiment, the heating device 4 is configured to heat the recording medium 1 with heated air. Instead, an infrared heater (including a far-infrared heater) is disposed inside the heating space. Thus, the recording medium 1 can be heated by an infrared radiant heat beam.
[0022]
The sublimation ink used in the image forming apparatus according to the present invention typically starts sublimation at about 80 ° C. and 180 ° C. in heat sublimation performed after being applied to the recording medium 1 as described above. A sublimation fixing state can be obtained with a heating time of about 2 minutes at the heating temperature. However, if the heating temperature is low or the heating time is short, the ink (printed dots before sublimation) is not sufficiently sublimated and the ink reaches the fixing layer 11 Because of the small amount of dye, the post-sublimation printed dots formed on the fixing layer 11 tend to have insufficient density instead of sharpness without diffusion. If the time is long, the sublimation of the ink (printed dots before sublimation) becomes excessive, and there are many ink pigments reaching the fixing layer 11. Instead the concentration of Todotto is made higher, the boundary line diffusion during sublimation is accompanied by the occurrence of bleeding increase becomes blurred tendency. As in the former case, if the printed dots after sublimation are sharp without blurring, the image formed by the printed dots after sublimation will also have high sharpness, and the printed after sublimation as in the latter case. If the dots exhibit a high density, as a result, the image formed by the printed dots after sublimation also has a wide range from the minimum density (so-called white) to the maximum density, and has a wide density dynamic range.
[0023]
As described above, the post-sublimation print dots finally obtained depending on the heating behavior by the heating device 4 on the recording medium 1 on which the image is formed on the surface layer 12 by the pre-sublimation print dots, that is, the heating temperature and the heating time. As a result, the sharpness and density dynamic range of the image formed on the fixing layer 11 change, and their schematic states are schematically shown in FIGS. Such a graph or table is created through a test print having a predetermined test pattern performed for each apparatus because the relationship between the heating behavior of the heating apparatus 4 and the sharpness and density dynamic range in the final image is slightly different for each apparatus. It is desirable that A high sharpness zone that obtains high sharpness at the expense of density dynamic range when the graph (function) or table shown in FIGS. 4 and 5 is created from a plurality of test prints performed at different heating temperatures and heating times. And a wide density dynamic range zone that obtains a wide density dynamic range at the expense of sharpness. There will be an intermediate zone between the high sharpness zone and the wide density dynamic range zone.
[0024]
When it is desired to drive the heating device 4 in the high sharpness control mode, the heating temperature and the heating time belonging to the high sharpness zone are used. When it is desired to drive the heating device 4 in the wide concentration dynamic range control mode, it belongs to the wide concentration dynamic range zone. Heating temperature and heating time may be used. In addition, when the heating time is constant, the state of the wide density dynamic range control mode can be created from the high sharpness control mode only by adjusting the heating temperature, and when the heating temperature is constant, A wide density dynamic range control mode can be created from the high sharpness control mode simply by adjusting the heating time.
[0025]
However, ink is applied to the recording medium 1 when the ink-jet head 2 reciprocates in the main scanning direction and the recording medium 1 is conveyed in the sub-scanning direction, and the recording medium 1 includes the ink-jet printing unit IU and the heat fixing unit. In an image forming apparatus configured to be transported continuously between HUs, the transport speed fluctuates depending on the print size, more precisely the print length in the main scanning direction, and consequently the time required to pass through the heating device 4. In other words, since the heating time varies, it is necessary to set the heating temperature for the high sharpness control mode and the wide density dynamic range control mode in consideration of the variation in the heating time depending on the print size.
[0026]
The inkjet 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. In order to grasp the position of the recording medium 1 conveyed by the conveyance mechanism 6, a sheet detection sensor 60 is installed at a predetermined position on the conveyance line formed by the conveyance mechanism 6, and the detection signal is also sent to the controller 7. Further, a recording medium type detection sensor 61 for detecting an ID code applied to the roll sheet cartridge or the shaft body that winds and supports the recording medium 1 is also installed to send the detection signal to the controller 7. The controller 7 can recognize the specification of the recording medium 1 loaded from this detection signal, for example, the length in the direction perpendicular to the transport direction, that is, the recording medium width.
[0027]
The controller 7 of the image forming apparatus includes a first controller 7A on the operating station OS side and a second controller 7B on the print station PS side, and is connected to each other via a communication cable so that data can be exchanged. It can function like
[0028]
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 F. Film scanner 85 that photoelectrically converts images into color image data, and data holding media (CD, CD-R, or MO, and communication that consists of data communication lines as well as semiconductor media such as compact flash and smart media) An image acquisition unit 84 (incorporated in the computer 80 here) that extracts color image data from the media), as described above, the heating device 4 in the high sharpness control mode or wide density dynamic range control mode, or if necessary Drive in an intermediate control mode A heating control mode switch 86 for instructing the image to be generated, and an appropriate test chart showing the degree of giving to the image sharpness and density dynamic range of the finally obtained heating temperature and heating time as shown in FIGS. A flat bed scanner 87 is provided as a density measuring device used when measuring the obtained test prints to obtain the relationship therebetween. 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 sent to the second controller 7B as print data after being subjected to various data processing and printed. A print image is formed on the recording medium 1 at the station PS, and the recording medium 1 is subjected to a heating sublimation process by the heating device 4 that is driven by the control mode set and input by the heating control mode switch 86.
[0029]
The controller 7 includes a first controller 7A and a second controller 7B, each having a microcomputer system including a CPU, a ROM, a RAM, an I / O interface circuit, and the like as core members. As shown in FIG. In the 1 controller 7A, peripheral devices such as an image acquisition unit 84 for sending image data, a film scanner 85, a flat bed scanner 87, and a heating control mode switch 86 are connected via an I / O interface circuit. In the controller 7B, 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 an I / O interface circuit. The first controller 7A and the second controller 7B can transmit data via their respective communication modules. For example, image data that has been subjected to image processing and correction processing in the first controller 7A is converted into final print data. After being transmitted to the second controller 7B via the communication modules 74a and 74b, it is used for applying sublimation ink to the recording medium 1.
[0030]
Each function by the controller 7 is created by hardware and / or software. However, here, if only the functional elements related to the present invention are listed, a print designated through the operation of the keyboard 82 and the mouse 83 by the operator will be described. A print size setting unit 70 for setting an image size, and image data transferred from the image data input unit 9 are subjected to resolution change and trimming based on the print image size set by the print size setting unit 70 and image correction setting. An image processing unit 72 that performs image correction processing such as color correction and head shading correction by interacting with the unit 72a, and for the inkjet head 2 using a binarization method such as error diffusion from image processed image data Print data production to create print data 5 is a relationship table between the heating temperature and the heating time and the high sharpness zone and the wide density dynamic range zone as shown in FIG. 5 based on the density value of the test chart of the test print sent from the unit 73 and the flat bed scanner 87. A control data management unit 90 for each heating control mode created with the help of an operator operation through a mouse operation or a keyboard operation, and drives the inkjet head 2 based on the transferred print data to discharge ink droplets from the ejection openings. The print control unit 75, the head feed control unit 76 that moves the inkjet head 2 in the main scanning direction simultaneously with the driving of the inkjet head 2, and the recording medium 1 is intermittently fed every time the inkjet head 2 moves in the main scanning direction. And a conveyance control unit for feeding the recording medium 1 to the heating device 4 7. Information such as the width of the recording medium 1 loaded from the heating control unit 78 for driving and controlling the electric heater 41 and the fan motor 44 of the heating device 4 and the ID code read by the recording medium type detection sensor 61 The recording medium type determining unit 79 to be acquired is a typical one. The heating control unit 78 controls the heating behavior in the heating device 4, for example, control data for each heating control mode based on the mode commanded from the heating control mode switch 86 that commands the high sharpness control mode or the wide concentration dynamic range control mode. A heating control mode setting unit 78a that receives the target heating temperature and / or the target heating time output by the management unit 90 is included. For example, the electric heater 41 is set so that the detection signal from the temperature sensor 42 matches the target heating temperature. Control etc. The heating time can be controlled by ON / OFF control of the electric heater 41 when the length of the heating space is sufficient, but when the length of the heating space is insufficient, the recording medium conveyance speed by the conveyance control unit 77 is controlled. Control is required.
[0031]
Next, how a captured image is formed on the recording medium 1 using color image data of the captured image read from the color negative film F using the film scanner 85 will be described with reference to a schematic flowchart of FIG.
[0032]
When the color negative film F is read by the film scanner 85, the CCD output signal of the film scanner 85 is amplified and AD converted and transferred to the image data input unit 71 as 12-bit RGB color image data (# 01). The color image data is subjected to typical correction as scanner data such as gamma correction in the image data input unit 71 and then sent to the image processing unit 72 (# 02). Before and after this, 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).
[0033]
The image processing unit 72 first converts the 12-bit color image data sent to 8-bit data, and then receives the print size from the print size setting unit 70 (# 04). Resolution conversion corresponding to, and trimming as necessary. Further, processing such as color correction normally performed in digital photo printing is performed manually or manually (# 05) through the operation of the keyboard 82 and mouse 83 by the operator. At the time of these correction processes, correction tables and filters suitable for the respective correction processes are loaded into the image processing unit 72 by the image correction setting unit 72a (# 06).
[0034]
In the image processing unit 72, the color image data subjected to all image processing is sent to the print data generation unit 73 (# 7). Since the RGB color image data is converted into CMYK color image data at an appropriate stage before and after other image processing in the image processing unit 72, the color image data sent to the print data generation unit 73 is CMYK color image data. is there.
[0035]
The print data generation unit 73 performs binarization processing for performing gradation formation by area gradation by the inkjet head 2 from the received 8-bit CMYK color image data, and generates binary CMYK print data, and the print control unit 75 (# 08).
[0036]
The print control unit 75 generates a drive pulse signal for the inkjet head 2 from the transferred binary CMYK print data (# 09), thereby controlling the drive element of the inkjet head 2 to the recording medium 1 Spray ink drops. At the same time, the head feed control unit 75 drives and controls the head feed mechanism 3, and the carry control mechanism 77 drives and controls the carry mechanism, whereby a photographic image is formed on the recording medium 1 (# 10).
[0037]
Regarding the heating behavior control of the heating device 4, first, based on the heating control mode (high sharpness control mode, wide density dynamic control mode) given from the heating control mode switch 86 (# 21), and depending on the case, the print size Considering also the print image size information sent from the setting unit 70 (# 22), the heating control mode control data management unit 90 sets the heating temperature suitable for the selected heating control mode, and the heating time if necessary. Is also sent to the heating control mode setting unit 78a of the heating control unit 78 (# 23). When the heating control mode setting unit 78 a sets the heating temperature sent from the heating control mode control data management unit 90 as the target temperature, the heating control unit 78 that controls the heating behavior of the heating device 4 receives the signal from the temperature sensor 42. The temperature of the heating space of the heating device 4 is adjusted while comparing (# 24). At that time, when adjustment of the conveyance speed of the recording medium 1, that is, adjustment of the heating time is necessary, the conveyance control unit 77 is instructed to change the conveyance speed.
[0038]
The recording medium 1 on which the photographed image is formed on the surface layer 12 is heated in a desired heating mode by passing through a heating space whose temperature is appropriately adjusted, and the photographed image is fixed to the fixing layer by the heating sublimation that occurs at that time. 11 is transferred (fixed). As a result, the final printed matter 100 having the desired sharpness or density dynamic range is finally obtained.
[0039]
The heating control mode switch 86 for instructing the control mode of the heating behavior in the heating device 4, that is, the high sharpness control mode, the wide concentration dynamic range control mode, and the intermediate control mode between these modes is set steplessly. You may comprise as a type to perform, and you may comprise as a type which sets between these modes in steps.
[Brief description of the drawings]
FIG. 1 is a cross-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 cross-sectional view showing the configuration of a print station of the image forming apparatus.
FIG. 4 is a schematic graph for explaining the relationship between the sharpness and density dynamic range of an image formed by post-sublimation print dots depending on the heating temperature and the heating time, and the relationship between sharpness and density dynamic range.
FIG. 5 is another graph for explaining the relationship between the sharpness and density dynamic range of an image formed by print dots after sublimation depending on the heating temperature and the heating time, and the relationship between sharpness and density dynamic range.
FIG. 6 is a functional block diagram for explaining the functions of the controller.
FIG. 7 is a schematic flowchart showing how a final printed matter is created by heating a recording medium having an image formed by an ink jet head driven based on input image data.
[Explanation of symbols]
1 Recording medium
2 Inkjet head
3 Head feed 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 controller
78 Heating control unit
78a Heating control mode setting section
86 Heating control mode selector
90 Control data management section by heating control mode

Claims (5)

By using a print head that is driven and controlled by print data created from image data, the recording medium with the ink applied to the surface layer is heated by a heating device, and the ink applied to the surface layer is transferred to the recording medium. In an image forming apparatus for sublimation fixing to a fixing layer,
There is provided a heating control unit that controls the heating behavior of the recording medium to determine the sublimation fixing characteristics from the surface layer of the ink to the fixing layer, and this heating control unit makes the heating of the recording medium insufficient. and high sharpness control mode which gives priority sharpness than the concentration dynamic range, the wide concentration dynamic range control mode over to the concentration dynamic range than sharpness prioritize by the heating of the recording medium to Yes,
A control data management unit for each heating control mode that creates a relationship table between the heating temperature, heating time, sharpness zone, and dynamic range zone from the density value of the test chart of the test print created by heating with the heating device. ,
The heating control section includes a heating control mode setting section that receives a target heating temperature and / or a target heating time output by the control data management section for each heating control mode and performs temperature control. apparatus.   The image forming apparatus according to claim 1, wherein a heating behavior between the high sharpness control mode and the wide density dynamic range control mode can be adjusted stepwise or steplessly.   The image forming apparatus according to claim 1, wherein the heating behavior is controlled by adjusting a heating temperature for the recording medium.   The image forming apparatus according to claim 1, wherein the heating behavior is controlled by adjusting a heating time for the recording medium.   The image forming apparatus according to claim 1, wherein the control of the heating behavior is performed by adjusting a heating temperature and a heating time for the recording medium.

Images