JP4320542B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus in which a sheet-like recording medium on which an image is formed by a print unit is heated by a heat fixing unit to fix the image on the recording medium.
[0002]
[Prior art]
As one of the conventional technologies in this field, a transparent transparent resin layer made of an acrylic resin, a polyester resin, or a urethane resin is used as a light transmissive resin layer on a colored base layer that also serves as a rust prevention layer formed on a metal substrate. After the resin layer is formed and the sublimation colorant is applied by inkjet printing to the ink jet receiving layer using porous alumina or the like formed thereon, the sublimation colorant is applied in a heating furnace or hot press. By heating, the sublimation coloring material of the ink jet receiving layer is sublimated to enter the transparent resin layer, and then the ink jet receiving layer is removed to create a metal decorative body in which a colored pattern is formed on the transparent receiving layer. (For example, refer to Patent Document 1). Such an image forming technique can be applied to a recording medium based on a metal with relatively little thermal deformation, but when applied to a recording medium based on a resin having a large thermal deformation. Can not avoid deformation after heating the substrate, especially wrinkles.
[0003]
As another conventional technique, heat transfer is performed by applying heat at a temperature as uniform as possible by a thermo-compression roller with temperature control in a state where a thermal transfer sheet on which a primary image is formed by an inkjet printer or the like is superimposed on a recording sheet. Some images (ink) formed on a sheet are transferred by heat sublimation to an ink fixing layer of a recording sheet, and then discharged from a casing (for example, see Patent Document 2). In this image forming technique, the heating temperature is strictly controlled. However, since the recording sheet after passing through the heat press roller is rapidly cooled, a heat sensitive material such as resin is applied to the recording sheet. When it is employed as a base material, it cannot prevent deformation such as wrinkles during cooling.
[0004]
In addition, in order to heat and fix the recording sheet on which the sublimation ink is transferred from the ink ribbon onto the surface, the recording sheet enters the heating box, and the recording sheet is opposed to each other with a slight gap formed in the heating box.・ Some recording sheets are heated by passing between a pair of heating rollers or between a heating roller and a conveying belt arranged along the peripheral surface of the heating roller and immediately discharged from the heating box. (For example, refer to Patent Document 3). Also in this image forming technology, the recording sheet heated by the heating roller is immediately discharged from the heating box to the outside and suddenly exposed to room temperature, so a heat sensitive material such as resin is used for the base of the recording sheet. In such a case, deformation such as wrinkles cannot be prevented during the cooling.
[0005]
Furthermore, in the field of textile printing technology, after applying a dye to the cloth by an ink jet method, the cloth is sent to a heating device to pass through the heating device in order to strengthen dyeing and improve color development. Some cloths are immediately discharged to the outside and cooled at room temperature (for example, see Patent Document 4). In this way, the configuration in which the recording medium (here, the cloth) is immediately exposed to the normal temperature state from the heating device is a wrinkle when the recording material is a heat sensitive material such as a resin. It is not possible to prevent such deformation.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-297197 (paragraph number 0010-0013, FIG. 4)
[0007]
[Patent Document 2]
Japanese Patent Laid-Open No. 10-16188 (paragraph number 0008-0012, FIG. 1)
[0008]
[Patent Document 3]
JP 2001-105638 A (paragraph numbers 0039-0058, FIG. 1)
[0009]
[Patent Document 4]
Japanese Patent Laid-Open No. 08-311782 (paragraph numbers 0041-0043, 0061-0070, FIG. 2)
[0010]
[Problems to be solved by the invention]
In view of the above situation, the problem of the present invention is that even if a recording medium based on a heat sensitive material such as a resin is used, the recording medium is deformed after heating by the heat fixing unit. It is an object of the present invention to provide an image forming apparatus capable of reducing the above.
[0011]
[Means for Solving the Problems]
In order to solve the above problems, in the image forming apparatus according to the present invention,
A slow cooling unit for gradually cooling the recording medium heat-fixed by the heat-fixing unit to a room temperature (room temperature) level;
The slow cooling unit includes a cooling guide body inclined downward ,
The cooling guide body includes a conveyance guide body that is in surface contact with the recording medium, and a heater that is arranged to be able to transfer heat to the conveyance guide body,
The heating wire constituting the heater is arranged so that the density of the heating wire gradually decreases from the recording medium entrance to the recording medium outlet of the slow cooling unit .
[0012]
With this configuration, the recording medium heated by the heat fixing unit for heat fixing of the print image is gradually returned from the ink fixing temperature (generally 150 ° C. or more) to the room temperature (room temperature) by the slow cooling unit. Occurrence of deformation such as wrinkles due to rapid cooling from the ink fixing temperature to room temperature due to sudden discharge from the heat fixing unit to the outside of the apparatus can be suppressed. As a result, a high-quality final printed matter with no noticeable wrinkles can be obtained.
[0013]
In order to gradually cool the recording medium that has come out of the heating and fixing unit with a uniform and continuous temperature gradient as much as possible , the slow cooling unit includes a conveyance guide body that makes surface contact with the recording medium, It is comprised from the heater arrange | positioned so that heat transfer is possible to a conveyance guide body. The layout of the heater that applies heat to the conveyance guide body is such that the surface temperature of the conveyance guide body gradually decreases from the heating temperature of the heat fixing unit to room temperature along the conveyance direction of the recording medium. Uniform and continuous cooling is possible.
[0014]
In order to easily realize the effective heater layout as described above, the heater is constituted by a heating wire, and the arrangement density of the heating wire is discharged from the recording medium entrance of the slow cooling unit. It is arranged so as to become gradually lower toward the exit. As a result, the surface temperature of the conveyance guide body gradually decreases from the heating temperature of the heat fixing unit to room temperature along the conveyance direction of the recording medium.
[0015]
Since the heating temperature in the heat fixing unit varies depending on the type of recording medium, the degree of gradual cooling with respect to the recording medium created by the slow cooling unit, that is, the temperature gradient characteristic in the recording medium conveyance direction created by the slow cooling unit is also provided. Configuring it to be variable creates a great advantage.
[0016]
The above-mentioned measures have made it possible to suppress the occurrence of deformation such as wrinkles due to rapid cooling from the ink fixing temperature to room temperature caused by sudden discharge from the heat fixing unit. It is difficult to correct deformations such as wrinkles already generated in the unit, that is, in the heated recording medium, by the slow cooling unit. This is because the slow cooling unit mainly focuses on preventing wrinkles generated on the recording medium during the cooling process. In order to realize a so-called ironing function that removes wrinkles that have already occurred in such a heating and fixing unit, in a preferred embodiment of the present invention, the heating region is connected to a region where the heating and fixing unit and the slow cooling unit are connected. Pressure applying means for applying pressure to the surface of the recording medium conveyed from the fixing unit to the slow cooling unit is provided. This pressure application means presses the surface of the recording medium to flatten the wrinkles of the recording medium that may have occurred in some cases. Such wrinkle stretching is suitably performed at the end of the heat fixing unit. This is because even if it is done at an early stage, it may occur again.
[0017]
One preferred embodiment of the pressure applying means is a pressure roller mechanism. By sandwiching and pressing from both sides of the recording medium with a pair of rollers or more, an ironing effect can be given to the recording medium being conveyed.
Other features and advantages of the present invention will become apparent from the following description of embodiments using the drawings.
[0018]
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.
[0019]
An example of an image forming system for producing the final printed matter 100 using such a recording medium 1 will be described with reference to FIGS. This image forming system includes a print station PS and an operating station OS as shown in FIG.
[0020]
The print station PS is fed from the ink jet print unit PU, a loop forming unit RU for temporarily storing the recording medium 1 on which a print image by pre-sublimation print dots is formed by the print unit PU, and the loop forming unit RU. A heat-fixing unit HU that applies heat energy to the recording medium 1 to produce a print image formed by print dots after sublimation, and the recording medium 1 that has come out of the heat-fixing unit is gradually cooled to a normal temperature (room temperature) level. The slow cooling unit CU is configured. At that time, the loop forming unit RU arranged between the print unit PU and the heat fixing unit HU has a transport speed of the recording medium 1 in the heat fixing unit HU lower than the average transport speed of the recording medium 1 in the print unit PU. It serves the purpose of absorbing this speed difference. The print unit PU, the loop forming unit RU, and the heat fixing unit HU are configured as units that are separable from each other. The slow cooling unit CU is attached to the heat fixing unit HU.
[0021]
As apparent from FIG. 4, in the print unit PU, the surface layer 12 as a print surface is printed while rewinding the recording medium 1 wound in a roll stored in a roll sheet cartridge (not shown). The recording medium 1 is conveyed by the sheet conveying mechanism 6 so as to come to the ink discharge port side of the ink jet print head 2 as a head. The print 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, and ink is ejected from the ejection port to the surface layer 12 of the recording medium 1. Each time the recording head 1 is moved 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. A plurality of discharge port modules capable of discharging different main colors for forming a color print image are prepared in the print 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 print head 2 mounted on a general-purpose inkjet printer is used, further description is omitted here. The recording medium 1 on which the print image is formed on the surface layer 12 by the ink droplets 2a ejected from the print head 2 exits the print unit PU and enters the loop forming unit RU.
[0022]
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 is a blade provided so as to be switchable between a position protruding toward the recording medium 1 with respect to the print head 2 and a position retracting in a direction away from the recording medium 1. A body 51 and a switching motor 52 that switches the position of the blade body 51 via a cam feed or screw feed mechanism (not shown) are provided.
[0023]
Although only schematically shown in FIG. 3, the loop forming unit RU includes a turn roller 32 having three driven rollers 31 at a central position, and is excellent in conveyance with reference to the turn roller 32. The first loop forming mechanism 30A on the side, the second loop forming mechanism 30B on the lower conveyance side with respect to the turn roller 32, and the case 33 for receiving the recording medium 1 at the lower position thereof.
[0024]
The turn roller 32 is driven by a motor (not shown), and the three driven rollers 31 are brought into pressure contact with the outer periphery of the turn roller 32 so that the recording medium 1 is turned to the turn roller 32 at a relatively large angle. It also functions to be able to remove the wrinkle of the recording medium 1 by winding. The first loop forming mechanism 30A has an introduction guide 34 for guiding the recording medium 1 discharged from the discharge port of the print unit PU downward, and the recording medium 1 guided downward by the introduction guide 34 further downward. The first fixed guide 35 to be guided and the first movable guide 36 disposed opposite to the first fixed guide 35 are configured. The first movable guide 36 is swingable around a swing axis provided at the upper end portion thereof, and the first movable guide 36 is closed by a motor (not shown) in a closed position indicated by a solid line and a virtual line. The swing is switched to the indicated open posture.
[0025]
The second loop forming mechanism 30B includes a second fixed guide 37 for guiding the recording medium 1 sent from the first loop forming mechanism 30A via the turn roller 32 to the heat fixing unit HU, and the second fixed guide. 37, a second movable guide 38 disposed opposite to the recording medium 37, and a pressure supply roller 39 for feeding the recording medium 1 to the heat fixing unit HU. The second movable guide 38 is swingable around a swing axis provided at the upper end thereof, and the second movable guide 38 is closed by a motor (not shown) in a closed position indicated by a solid line and a virtual line. The swing is switched to the indicated open posture.
[0026]
In this loop forming unit RU, sensors (not shown) for determining the presence or absence of the recording medium 1 are arranged at various points along the conveyance path of the recording medium 1, and based on detection signals from these sensors. The control described below is executed. That is, when the recording medium 1 is discharged from the print unit PU, the leading end of the recording medium 1 is introduced by rotating the turn roller 32 at a low speed while setting the first movable guide 36 in the closed posture. When the guide 34 is guided from the guide 34 to the turn roller 32 and it is confirmed that the turn roller 32 and the driven roller 31 press and hold the tip of the recording medium 1, the turn roller 32 is stopped, and then the first movable guide. 36 is switched to the open posture, and the recording medium 1 is stored in the form of hanging down in the space of the first loop forming mechanism 30A. Next, when the rear end of the recording medium 1 sent out from the print unit PU is detected, the turn roller 32 and the supply roller 39 are started to be driven while the second movable guide 38 is set in the closed posture. The leading end of the recording medium 1 is fed to the supply roller 39 of the second loop forming mechanism 30B, and the leading end of the recording medium 1 is pressure-bonded by the supplying roller 39 at a speed equal to the conveying speed of the recording medium 1 in the heat fixing unit HU. While the second movable guide 38 is switched to the open posture while performing the operation of feeding it to the heat fixing unit HU, the turn roller 32 is rotated at a high speed so that the recording medium 1 stored in the first loop forming mechanism 30A is second. Control for storing the recording medium 1 in the form of hanging down in the space of the loop forming mechanism 30B is performed. As described above, when the recording medium 1 of the first loop forming mechanism 30A is sent out to the second loop forming mechanism 30B, the control to introduce the recording medium 1 from the print unit PU into the first loop forming mechanism 30A as described above. Is started.
[0027]
A heat fixing unit HU schematically shown in FIG. 3 and shown in detail in FIG. 5 includes a heating case 51 made of a heat insulating material for heating the recording medium 1 inside the main body case 50, and A blower case 52 made of a heat insulating material disposed at an upper position of the heating case 51 so as to supply heated air to the heating case 51 and a support leg 53 for supporting the main body case 50 are provided. In the heating case 51, a preheating space PR is formed on the entrance side, and a heating space R is formed following the preheating space PR. A heating and conveying mechanism 54 that conveys the recording medium 1 is disposed as a part of the sheet conveying mechanism 6 in the preheating space PR and the heating space R. The heating / conveying mechanism 54 includes a pair of pressure-bonding introduction rollers 54a provided on the inlet side of the heat fixing unit HU, and the surface of the recording medium 1 in the heating space R with the two rollers on the back surface of the recording medium 1. Are arranged in the preheating space PR to contact the lower surface of the recording medium 1 and to transfer heat to the recording medium 1. One guide body 54c and two guide bodies 54c disposed in the heating space R, a plurality of upper surface contacts that are disposed above the guide body 54c and that contact the upper surface of the recording medium 1 and exert a conveying force. It includes a roller 54d, a pressure roller mechanism 58 provided on the outlet side of the heat fixing unit HU, and a curved conveying portion 59 provided immediately on the lower conveyance side of the pressure roller mechanism 58.
[0028]
As shown in FIGS. 6 and 7, the pressure roller mechanism 58 is disposed at a position closer to the conveyance upper side than the first roller 58 a and the first roller 58 a in contact with the back surface of the recording medium 1. A second roller 58b that comes into contact with the surface, a third roller 58c that is disposed at a lower conveyance position than the first roller 58a and that comes into contact with the surface of the recording medium 1, and a roller shaft 58d of these rollers can be rotated. It is comprised from the bracket 58e to support. The roller shaft 58d of the third roller 58c is inserted into a vertical guide hole 58f provided in the bracket 58e, whereby the third roller 58c presses the recording medium 1 with the first roller 58a by its own weight. It will be. Each roller of the pressure roller mechanism 58 has a length longer than the maximum width of the recording medium 1 and a foamed resin layered on the surface of the metal drum. The weight of the third roller 58c is the first. The recording medium 1 is pressed against the one roller 58a so as to produce an iron effect that stretches wrinkles generated on the recording medium 1 during heat fixing. The self-weight is determined experimentally and empirically according to the roller length, but the self-weight adjustment is performed by a weight provided additionally. Needless to say, the third roller 58c may be configured to be biased toward the recording medium 1 by a spring or the like. As is apparent from FIG. 7, the recording medium 1 is slightly curved in this pressure-bonding region because the axial center of the third roller 58c is deviated from the axial center of the first roller 58a in the transport direction. The ironing effect is further enhanced.
[0029]
Note that all the rollers constituting the heating and conveying mechanism 54 are driven directly or indirectly via a transmission belt (not shown). At this time, the third roller 58c is configured such that its roller shaft 58d moves far and away with respect to the recording medium 1, but it can be driven by a transmission mechanism including a well-known tension adjusting pulley. It is.
[0030]
Further, the curved conveyance unit 59 is constituted by a guide body having a guide surface such that the surface on which the image is formed on the recording medium 1 faces outward. When the recording medium 1 moves while in contact with the surface of the guide body 59, a pulling force is generated on the surface side, and this force plays a role of extending fine surface wrinkles.
[0031]
A sheet heater 55 that heats the guide body 54c on the lower surface side of the guide body 54c disposed below the upper surface contact roller 54d, and a fixing that measures the temperature of the guide body 54c relative to the center position of the sheet heater 55. A temperature sensor 41 is provided. If necessary, a sheet heater and a temperature sensor may be provided on the guide body constituting the curved conveyance unit 59 to perform feedback temperature control.
[0032]
Inside the blower case 52, there are a plurality of rod-shaped electric heaters 56 and a cross flow fan that drives the fan around an axis that is parallel to the width direction of the recording medium 1 so as to send heated air. 57 is provided. On the lower surface side of the blower case 52, a heated air discharge port E is formed at a position directly below the cross flow fan 57, and a suction port F is formed at the upper transport position of the transport path of the recording medium 1 in the heating transport mechanism 54. ing. An air temperature sensor 42 is disposed at the opening of the discharge port E corresponding to the cross flow fan 57.
[0033]
When the recording medium 1 is heated, the electric heater 56 and the cross flow fan 57 are driven, so that the heated air heated inside the blower case 52 is discharged from the discharge port E to the recording medium 1 in the internal space of the heating case 51. With respect to the lower side position in the transport direction, the recording medium 1 is sent out with a width exceeding the entire width in the width direction, and this heated air flows toward the upper transport side along the transport path of the recording medium 1 in the heating space R. Then, the air is sucked from the upper position in the conveyance direction of the recording medium 1 into the blower case 52 through the suction port F, heated by the electric heater 56, and then supplied to the cross flow fan 57 to circulate the heated air.
[0034]
At the time of heat fixing control, the electric power supplied to the corresponding electric heater 56 is controlled by the air temperature sensor 42 to measure the temperature of about 180 ° C., and the temperature of about 100 ° C. is measured by the fixing temperature sensor 41 in the preheating space PR. Then, the electric power supplied to each sheet heater 55 measures the temperature of about 130 ° C. with the conveyance upper fixing temperature sensor 41 in the heating space R and measures the temperature of 180 ° C. with the conveyance lower fixing temperature sensor 41. Be controlled.
[0035]
As shown in FIGS. 5 and 6, the slow cooling unit 90 includes a slow cooling guide body 92 as a transport guide body for the recording medium 1, a slow cooling intermediate transport roller pair 94, a direction changing guide 95, and a discharge roller pair 96. In addition to this, a slow cooling conveyance line for the recording medium 1 inclined downward is created. This slow cooling conveyance line is disposed in a slow cooling space substantially closed by a slow cooling case 91. The slow cooling guide body 92 extends with a width exceeding the maximum width of the recording medium 1 in order to form an inclined guide surface in surface contact with the recording medium 1, and the inclination angle is 20 ° to 60 ° with respect to the vertical axis. Determined between °. On the back side of the slow cooling guide body 92, a heating wire 93 as a heater capable of transferring heat to the slow cooling guide body 92 is disposed.
[0036]
Further, the recording medium entrance area of the slow cooling guide body 92 is substantially equal to the outlet temperature of the heat fixing unit HU, and the recording medium discharge area of the slow cooling guide body 92 is substantially equal to room temperature. By adjusting the heat transmitted from the heating wire 93 to the slow cooling guide body 92 so that the temperature gradient in the meantime is as smooth as possible, deformation such as wrinkles generated in the recording medium 1 during the cooling process is suppressed. be able to. For this reason, as shown in FIG. 8, the heating wire 93 is provided so that the arrangement density is higher on the conveyance upper side and the arrangement density is lower on the conveyance lower side than the slow cooling guide body 92. . In order to make the temperature gradient as gentle as possible, a meandering layout in which the arrangement pitch is continuously changed as shown in FIG. 9 may be adopted. In the embodiment of FIGS. 8 and 9, the heating wire 93 is composed of a single wire, and the temperature generated in the slow cooling guide body 92 increases and decreases by changing the amount of power supplied to the heating wire 93.
[0037]
By flowing a predetermined current through the heating wire 93, a cooling temperature gradient that suppresses the occurrence of wrinkles as described above in the slow cooling guide body 92, for example, a temperature gradient from about 180 ° C. to 20 ° C. is created. The power supply control to the heating wire 93 is accurately performed by the controller 7 while using the detection signal from the slow cooling temperature sensor 43 provided directly in the intermediate region of the slow cooling guide body 92 or above the guide surface as feedback.
[0038]
As an embodiment in which the temperature gradient in the transport direction in the slow cooling guide body 92 can be arbitrarily adjusted, for example, as shown in FIG. 10, the heating wire 93 is connected from the recording medium entrance area to the recording medium discharge area. The first heating wire 93a, the second heating wire 93b, the third heating wire 93c, the fourth heating wire 93d,... It is also possible to adopt. In this case, a plurality of slow cooling temperature sensors 43a, 43b, 43c, 43d,... Are arranged at positions corresponding to the heating wires 93a, 93b, 93c, 93d, etc., and each heating wire is individually feedback controlled. Thus, an arbitrary temperature gradient is created in the slow cooling guide body 92 as a whole. This configuration is particularly advantageous in cases where the fixing temperature varies greatly depending on the type of the recording medium 1 or the room temperature varies greatly depending on the season.
[0039]
A stocker ST is provided as shown in FIGS. 2 and 3 to receive the recording medium 1 discharged from the slow cooling unit CU. The stocker ST is formed in a box shape having a width wider than the maximum width of the recordable recording medium 1, and the inside is lined with a sheet woven with conductive carbon fibers so as to remove static electricity. Yes. Since the recording medium 1 discharged from the slow cooling unit TU has a certain amount of curl, the core is wound and stored in the stocker ST using the curl. In the recording medium 1 wound up and stored, the ink (pigment) forming the print image is fixed on the fixing layer 11, so that the surface layer 12 is peeled off to thereby have a final color-developed image. A printed material 100 is obtained.
[0040]
The controller 7 functioning as the control unit of the image forming system configured as described above includes a first controller 7A on the operating station OS side and a second controller 7B on the print station PS side. They are connected interchangeably and can function like a single controller.
[0041]
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 (which is built in the computer 80 in this case) that extracts color image data from a medium) is provided. In this image forming system, the image data transferred to the first controller 7A through the film scanner 85 and the image acquisition unit 84 is subjected to various necessary image processing, and then sent to the second controller 7B as print data for printing. A print image is formed on the recording medium 1 at the station PS and is fixed by heating.
[0042]
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 first controller 7A, peripheral devices such as an image acquisition unit 84 and a film scanner 85 for sending image data are connected via an I / O interface circuit. In the second controller 7B, a peripheral device such as an image acquisition unit 84 is connected via an I / O interface circuit. Peripheral devices incorporated in the print station PS such as the ink jet print head 2, the head feed mechanism 3, the electric heater 56, the cross flow fan 57, and the recording medium transport mechanism are connected. Further, a recording medium type detection sensor 44 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 type of the recording medium 1 loaded from the detection signal. 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.
[0043]
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 specifically mentioned, image data captured from the image acquisition unit 84 or the film scanner 85 is used. An image data input unit 71 that performs preprocessing such as format conversion and resolution conversion on the image data, and an image processing unit 72 that performs image correction processing such as trimming and color correction on the image data transferred from the image data input unit 71 Based on the transferred print data, the print data generation unit 73 generates print data for the print head 2 from the final image data subjected to image processing using a binarization technique such as error diffusion. A print control unit 7 that drives the print head 2 to discharge ink droplets from the ejection openings. , Intermittent feeding of the recording medium 1 synchronized with the movement of the print head 2 in the main scanning direction in the print unit PU, loop conveyance of the recording medium 1 in the loop forming unit RU, and recording medium in the heating and fixing unit HU A conveyance control unit 76 for controlling the heating and conveyance of the recording medium 1 from the heating and cooling unit CU (by the slow cooling intermediate conveyance roller pair 94 and the discharge roller pair 96), the electric heater 56 of the heating and fixing unit HU, Heating control unit 77 that drives and controls the crossflow fan 57, and detection of the slow cooling temperature sensor 43 (43a...) Feeding power to the heating wire 93 (93a...) As a heater for the slow cooling guide body 92. The type information of the recording medium 1 loaded is obtained from the ID code read by the slow cooling control unit 78 controlled by the temperature and the recording medium type detection sensor 44. Such as the recording medium type determining unit 79 which are representative. The slow cooling control unit 78 controls the power supply to the heating wire 93 (93a...) Taking into account information such as the recording medium type used and the room temperature by the recording medium type determining unit 79 as necessary. be able to.
[0044]
A typical work flow for producing a final printed matter using such an image forming system will be described below.
1. First, image data in JPEG format read from the MO disk using the image acquisition unit 84 is transferred to the image data input unit 71 as an image source of the image forming apparatus. The JPEG image data is expanded into 8-bit RGB color image data by the image data input unit 71 and sent to the image processing unit 72. Next, the image data is processed based on the print image size, trimming setting command, and color correction command input by the operator operating the keyboard 82 and mouse 83. When the predetermined image processing is completed, the image data is sent to the print data generation unit 73. 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. It is. The print data generation unit 73 converts the CMYK color image data into binary CMYK print data and transfers it to the print control unit 75. As described above, the print control unit 75 generates a drive pulse signal for the print head 2 from the transferred binary CMYK print data, thereby controlling the drive element of the print head 2 to record the recording medium 1. An image is formed by ink dots.
[0045]
2. The recording medium 1 on which the image is formed on the surface layer 12 of the image fixing formation stage passes through the preheating space PR and the heating space R that are appropriately temperature-adjusted after being subjected to the necessary time adjustment by the loop forming unit RU. Accordingly, the image formed on the surface layer 12 is transferred (fixed) to the fixing layer 11 by heat sublimation caused by the heat sublimation. The recording medium 1 that has undergone the heat fixing process is stretched by the ironing effect of the wrinkles generated in the heating process by a pressure roller mechanism 58 as a pressure applying means disposed at the outlet of the heat fixing unit HU, and further, a curved conveying unit. The surface is pulled and shaped by 59 and fed into the slow cooling unit CU.
[0046]
3. Recording medium slow cooling stage The recording medium 1 fed into the slow cooling unit CU descends obliquely downward along the surface of the slow cooling guide body 92, and is sandwiched between the slow cooling intermediate conveyance roller pair 94. By a direction changing guide 95 and a discharge roller pair 96 disposed below, it is returned to a substantially horizontal posture and discharged outside. The discharged recording medium 1 is accommodated in the stocker ST, and the surface layer 12 is peeled off at an appropriate time, whereby a final printed matter 100 having a finely colored image is obtained.
[0047]
In the embodiment described above, an image forming system that includes the print station PS and the operating station OS, and the print station PS includes the print unit PU, the loop forming unit RU, the heating and fixing unit HU, and the slow cooling unit CU is taken up. Although described, the minimum components of the image forming apparatus according to the present invention are the heat fixing unit HU and the slow cooling unit CU. Of course, an image forming apparatus including all other units or partially including other units can be handled.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating an example of a recording medium handled in the present invention. FIG. 2 is an external view illustrating an embodiment of an image forming apparatus according to the present invention. FIG. 3 is a schematic cross-sectional view illustrating a configuration of a print station. 4 is a schematic cross-sectional view showing the configuration of the print unit. FIG. 5 is a schematic cross-sectional view showing the configuration of the heat fixing unit and the slow cooling unit. FIG. 6 is an enlarged schematic cross-sectional view showing the configuration of the pressure roller mechanism. FIG. 8 is a perspective view showing a configuration of a pressure roller mechanism and a slow cooling unit. FIG. 9 is another layout of a heating wire provided in the slow cooling guide body. FIG. 10 is a schematic diagram showing the layout of another embodiment of the heating wire provided in the slow cooling guide body. FIG. 11 is a functional block diagram explaining the function of the controller.
DESCRIPTION OF SYMBOLS 1 Recording medium 6 Conveyance mechanism 7 Controller 7A 1st controller 7B 2nd controller 58 Pressurizing roller mechanism 59 Curve conveyance part 76 Conveyance control part 77 Heating control part 78 Slow cooling control part 79 Recording medium type determination part 91 Slow cooling case 92 Slow cooling guide body 93 Heating wire (heater)
94 Slow cooling intermediate transport roller 95 Direction change guide 96 Discharge roller PU Print unit RU Loop forming unit HU Heat fixing unit CU Slow cooling unit

Claims (4)

In the image forming apparatus for fixing the image to the recording medium by heating the sheet-like recording medium on which the image is formed by the print unit by the heat fixing unit,
A slow cooling unit for gradually cooling the recording medium heat-fixed by the heat-fixing unit to a normal temperature level;
The slow cooling unit includes a cooling guide body inclined downward ,
The cooling guide body includes a conveyance guide body that is in surface contact with the recording medium, and a heater that is arranged to be able to transfer heat to the conveyance guide body,
The image forming apparatus according to claim 1, wherein the heating wire constituting the heater is arranged so that a density of the heating wire gradually decreases from a recording medium entrance to a recording medium discharge port of the slow cooling unit .   The image forming apparatus according to claim 1, wherein the slow cooling unit further includes a direction changing guide for changing a direction of the recording medium discharged from the cooling guide body to a horizontal posture. The image forming apparatus according to claim 1 or 2 recording medium Xu Hiyado receive within the slow cooling unit is characterized in that it is modified. A pressure applying unit that applies pressure to the surface of the recording medium conveyed from the heat fixing unit to the slow cooling unit is provided in a connection region between the heat fixing unit and the slow cooling unit. the image forming apparatus according to any one of claims 1-3.

Images