JP2010194791A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus having an ultrasonic cleaning means capable of efficiently performing cleaning of a thermal head, and a drying means. <P>SOLUTION: The image forming apparatus is characterized by having at least a means for conveying a medium to be transferred and an image writing means for forming an image on the medium to be transferred by using one or more thermal heads and thermal transferring ribbons, by providing the thermal heads on a thermal head unit, and by including the ultrasonic cleaning means for cleaning the thermal head in the neighborhood of the thermal head unit, and a movable mechanism on the thermal head unit for moving the thermal heads to the ultrasonic cleaning means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a thermal transfer type image forming apparatus, and more particularly to an image forming apparatus having a thermal head cleaning means.

  FIG. 1 is a cross-sectional view showing an example of a thermal transfer ribbon used in a thermal transfer image forming apparatus. The thermal transfer ribbon 1 is a ribbon base 2 provided with a thermal transfer layer 3.

  The thermal transfer image forming apparatus has a direct transfer method and an intermediate transfer method. FIG. 2 is a diagram showing an outline of a printing mechanism of a direct transfer type thermal transfer image forming apparatus. A thermal transfer ribbon 11 is supplied from a ribbon unwinding roll 12 and passes through a roller 13 and then generates heat by applying a voltage. A thermal head 14 in which a plurality of bodies are arranged is pressed from the ribbon base surface of the thermal transfer ribbon 11. The printing paper 15 is supplied from the printing paper unwinding roll 16 and is in contact with the thermal transfer layer of the thermal transfer ribbon 11 pressed on the platen roll 17, and the transfer layer is transferred onto the printing paper 15 to form an image. After being transferred, the thermal transfer ribbon 19 passes through the roll 18 and is then wound around the ribbon winding roll 20.

  FIG. 3 is a diagram showing an outline of a printing mechanism of an intermediate transfer type thermal transfer image forming apparatus. The thermal transfer ribbon 21 is supplied from a ribbon unwinding roll 22, passes through a roller 23, and then is heated by the thermal head 24. It is pressed from the ribbon substrate surface. The intermediate transfer film 31 is supplied from an intermediate transfer film unwinding roll 32, passes through a roller 33, and then comes into contact with the thermal transfer layer of the thermal transfer ribbon 21 pressed on the platen roll 27 to transfer the transfer layer. The printing paper 25 is supplied from the printing paper unwinding roll 26, and the transfer layer transferred to the intermediate transfer film is transferred to the printing paper 25 by the rollers 35 and 36 of the secondary transfer unit 34, and is transferred via the roll 37. An image is formed on the printed paper 25. After the transfer, the intermediate transfer film 39 is wound around an intermediate transfer film winding roll 40 after passing through a roller 38. In addition, the thermal transfer ribbon 29 after being transferred on the platen roll 27 is wound around the thermal transfer ribbon winding roll 30 via the roll 28.

  The thermal transfer image forming apparatus is characterized by small size, low price, easy maintenance, low noise, etc., both in the direct transfer system and the intermediate transfer system, and widely used, but because the thermal transfer ribbon is in contact with the thermal head, When the thermal head is used for a long time, foreign matters such as debris and dust and wax for improving the lubricity of the thermal transfer ribbon and the thermal head adhere to the surface of the thermal head. For this reason, there is a drawback in that foreign matter obstructs thermal transfer and color loss occurs in the portion, resulting in a decrease in print image quality, and a convenient cleaning method is required.

  Conventionally, the thermal head cleaning method differs depending on the material of the surface on which the heating element is provided, but generally a soft cloth is soaked with a solvent such as IPA (isopropyl alcohol) periodically or with poor printing. It is done by wiping its surface as it occurs.

  By using a thermal transfer ribbon 5 in which a cleaning agent layer 4 is provided on the opposite surface of the thermal transfer layer 3 of the ribbon substrate 2 shown in FIG. A method of cleaning has also been devised (Patent Document 1).

JP-A-5-147324 JP-A-6-72046

  However, in the conventional method in which a soft cloth is soaked with a solvent such as IPA and the conventional method using a thermal transfer ribbon provided with a cleaning agent layer on the opposite side of the thermal transfer layer of the transfer ribbon substrate, for example, the former In this method, the periphery of the surface of the thermal head where the heating element is provided is difficult to perform because of the small space, and the number of times of cleaning increases when cleaning is performed regularly. This causes a problem that the printing and recording efficiency is lowered, and that the dust in the air adheres to the inside of the image forming apparatus because the cover of the image forming apparatus is opened during cleaning. Further, in the latter method, there arises a problem of increasing the cost of the thermal transfer ribbon itself by providing the cleaning agent layer.

  The present invention has been made in view of the above problems, and provides an image forming apparatus capable of cleaning a thermal head efficiently and without increasing the cost of a thermal transfer ribbon.

  As means for solving the above-mentioned problems, the invention according to claim 1 is characterized in that at least a transfer medium is transferred, and an image writing means for forming an image using at least one thermal head and a thermal transfer ribbon on the transfer medium. The thermal head is provided in the thermal head unit, and includes an ultrasonic cleaning means for cleaning the thermal head in the vicinity of the thermal head unit. The thermal head unit includes a movable mechanism for moving the thermal head to the ultrasonic cleaning means. An image forming apparatus characterized by that.

  The invention described in claim 2 is characterized in that a drying means for drying the cleaned thermal head is provided in the vicinity of the thermal head unit, and the movable mechanism moves the cleaned thermal head to the drying means. The image forming apparatus according to claim 1.

  According to a third aspect of the present invention, the thermal head unit includes a columnar main body portion and a thermal head portion provided in the main body portion, and the movable mechanism is a rotation mechanism that rotates about the central axis of the columnar main body portion as a rotation axis. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.

  The invention according to claim 4 is characterized in that the thermal head unit includes a flat plate-like main body portion and a thermal head portion provided in the main body portion, and the movable mechanism is a slide mechanism that slides the thermal head unit. The image forming apparatus according to claim 1 or 2.

  According to the image forming apparatus of the present invention, since the thermal head is cleaned by ultrasonic waves without providing a cleaning agent layer on the thermal transfer ribbon, the cloth does not directly contact the thermal head. In addition, it is possible to remove foreign matters fixed to the thermal head and foreign matters clogged in the surface of the thermal head. Furthermore, since a plurality of thermal heads are provided, printing can be performed by the other thermal head even when one is being washed, and therefore printing is not stopped by washing, so that a reduction in printing efficiency can be prevented. Further, by regularly cleaning the head, foreign matter can be prevented from being accumulated, and the defective rate of print recording can be reduced.

The figure which showed in cross section an example of the thermal transfer ribbon used for a thermal transfer type image forming apparatus. 1 is a diagram showing an outline of a printing mechanism of a direct transfer type thermal transfer image forming apparatus. 1 is a diagram showing an outline of a printing mechanism of an intermediate transfer type thermal transfer image forming apparatus. The figure which shows the transfer ribbon used for another washing | cleaning method. (A) is a figure which shows a cross section. (B) is a plan view. 1 is a diagram illustrating an outline of an image forming apparatus according to an embodiment of the present invention using an intermediate transfer method as an example. The figure which showed the thermal head peripheral part 60 of FIG. 5 in detail. FIG. 6 is a view showing another example of a thermal head unit of the image forming apparatus according to the embodiment of the present invention. (A) is a figure which shows the thermal head unit which has four thermal heads. (B) is a figure which shows the thermal head unit which has six thermal heads. FIG. 3 is a diagram showing that the main body of the thermal head unit of the image forming apparatus according to the embodiment of the present invention is cylindrical. FIG. 4 is a diagram illustrating operations of a thermal head unit, an ultrasonic cleaning unit, and a drying unit of the image forming apparatus according to the embodiment of the present invention. (A) is a diagram showing a state 1; (B) is a diagram showing a state 2; (C) is a diagram showing a state 3; FIG. 3 is a diagram illustrating an example of arrangement of a thermal head, an ultrasonic cleaning unit, and a drying unit in the image forming apparatus according to the present invention. (A) is the figure which has arrange | positioned the ultrasonic cleaning part and the drying part in this order from the position near a thermal head. FIG. 6B is a diagram in which an ultrasonic cleaning unit and a drying unit are arranged at positions of the thermal head unit different from the transfer state. FIG. 4 is a diagram illustrating an example of a position of a thermal head provided in a thermal head unit in the image forming apparatus according to the present invention. (A) is the figure with which the thermal head was equipped in the side surface of the columnar main body. FIG. 5B is a diagram in which the thermal head is provided on the upper surface of the columnar body. FIG. 6 is a diagram showing an example in which another thermal head unit in the image forming apparatus according to the present invention includes a slide mechanism. FIG. 10 is a diagram illustrating operations of a thermal head unit, an ultrasonic cleaning unit, and a drying unit different from FIG. 9 in the image forming apparatus according to the present invention. (A) is a diagram showing a state 1; (B) is a diagram showing a state 2; The figure which shows the example provided with the slide mechanism in the example of the thermal head unit different from FIG. 12 in the image forming apparatus which concerns on this invention. 1 is a schematic diagram illustrating an image forming apparatus according to the present invention using an intermediate transfer method as an example.

  An embodiment for carrying out an image forming apparatus according to the present invention will be described with reference to the drawings.

  FIG. 5 is a diagram showing an outline of an image forming apparatus according to an embodiment of the present invention, taking an intermediate transfer method as an example. The thermal transfer ribbon 41 is supplied from a ribbon unwinding roll 42 and is transferred onto a platen roll 47 via a roller 43. On the platen roll 47, the thermal transfer substrate 41 of the thermal transfer ribbon 41 is pressed by the thermal head 44-1. An intermediate transfer film 51 as a transfer medium is transferred to a platen roll 47 by a transfer means having an intermediate transfer film unwinding roll 52 and a roller 53, and the thermal head 44-1 and the thermal transfer ribbon 41 are used on the platen roll 47. The transfer layer of the thermal transfer ribbon 41 is transferred and written onto the intermediate transfer film 51 as the transfer medium by the image writing means. The printing paper 45 is supplied from the printing paper unwinding roll 46, and the image transferred to the intermediate transfer film is transferred to the printing paper 45 by the rollers 55 and 56 of the secondary transfer unit 54, and the image is written. After the transfer, the intermediate transfer film 58 is wound around an intermediate transfer film take-up roll 59 after passing through a roller 57. The thermal transfer ribbon 49 after being transferred on the platen roll 47 is wound around the thermal transfer ribbon winding roll 50 after passing through the roll 48. The printing paper 45 may be a wound paper or a sheet.

  FIG. 6 is a diagram showing the thermal head peripheral portion 60 of FIG. 5 in detail. The thermal head section includes a thermal head 44-2 and a thermal head 44-3 in addition to the thermal head 44-1. The thermal head unit 61 is composed of a columnar main body 64 (showing a triangular column in FIG. 6) and a thermal head composed of a thermal head 44-1, a thermal head 44-2, and a thermal head 44-3. A rotation mechanism that rotates with a central axis 65 of the 64 as a rotation axis is provided, and the positions of the thermal head 44-1, the thermal head 44-2, and the thermal head 44-3 can be changed by the rotation mechanism. . After the transfer of one screen is completed and before the transfer of the next screen starts, either the platen roll 47 or the thermal head unit 61 is moved to increase the distance between the platen roll 47 and the thermal head unit 61. The thermal head unit 61 is rotated by the rotation mechanism. Further, in the vicinity of the thermal head unit 61, an ultrasonic cleaning unit 62, which is an ultrasonic cleaning means for cleaning the thermal head, is provided.

  The ultrasonic cleaning unit 62 may have a structure in which an ultrasonic vibration element is closely attached to a thermal head and performs ultrasonic cleaning in the air. However, in order to enhance the cleaning effect, the thermal head 44-1 or the thermal head 44-2 is used. Alternatively, it is desirable to employ a structure in which the thermal head 44-3 is cleaned by being submerged in water in the ultrasonic cleaning layer using a conventionally used ultrasonic cleaning tank.

  Further, in the vicinity of the thermal head unit 60, there is provided a drying unit 63 which is a drying means for drying the cleaned thermal head. In the embodiment of the present invention, the drying unit 63 can exemplify a hot air drying structure in which hot air is blown onto the thermal head, but an infrared lamp or the like may be used without being limited thereto.

  In the embodiment of the present invention, the thermal head unit including three thermal heads is used. However, the number of thermal heads is not limited to this, and one or more thermal heads may be appropriately employed. For example, FIG. 7 is a view showing another example of the thermal head unit of the image forming apparatus according to the embodiment of the present invention, and FIG. 7A shows four (thermal heads 67-1 to 67-4) thermal heads. The thermal head unit 66 having a central axis 65-2 of the columnar main body portion 64-2 is rotated as a rotation axis. FIG. 7B shows a thermal head unit 68 having six (thermal heads 69-1 to 69-6) thermal heads, and the central axis 65-3 of the columnar main body 64-3 serves as a rotation axis. Rotate. Further, the columnar body portion 64-2 of the thermal head unit 66 and the columnar body portion 64-3 of the thermal head unit 68 are polygonal columnar shapes, but are not limited thereto, and a columnar body as shown in FIG. The part 132 can also be employed. FIG. 8 shows a thermal head 130 having six thermal heads (131-1 to 131-6). The thermal head unit 130 rotates with the central axis 133 of the main body 132 of the thermal head unit 130 as a rotation axis. To do.

  Next, operations of the thermal head unit, the ultrasonic cleaning unit, and the drying unit of the image forming apparatus according to the embodiment of the present invention will be described with reference to FIG. 9A shows the state 1, FIG. 9B shows the state 2, and FIG. 9C shows the state 3. 44-1, 44-2 and 44-3 are thermal heads, 64 is a columnar main body of the thermal head unit 61, 65 is a central axis around which the columnar main body 64 rotates, 62 is an ultrasonic cleaning unit, and 63 is dry. Reference numeral 47 denotes a platen roll.

9A, the thermal transfer layer of the thermal transfer ribbon pressed by the thermal head 44-1 on the platen roll 47 is transferred and transferred using the thermal head 44-1 and a thermal transfer ribbon (not shown). An image is written on an intermediate transfer film (not shown) as a medium, and the thermal head 44-2 has already been cleaned by the ultrasonic cleaning unit 62 and dried by the drying unit 63. It is in a state where moisture has been removed. Furthermore, the thermal head 44-3 is in a cleaning standby state by the ultrasonic cleaning unit 62, and is cleaned immediately before the state 2 in FIG. 9B.

  The transition from the state 1 in FIG. 9A to the state 2 in FIG. 9B is that the platen roll 47 first moves in the direction opposite to the thermal head 44-1, and then the central axis of the columnar body 64. 65 is performed by rotating in the direction of the arrow 65 as a rotation axis. Alternatively, after the platen roll 47 is fixed, the thermal head unit and ultrasonic cleaning unit 62 and the drying unit 63 move in the opposite direction to the platen roll 47, and then the central axis 65 of the columnar main body 64 is the rotation axis. This is done by rotating in the direction of the arrow. When the thermal head unit is rotating, the ultrasonic cleaning unit 62 and the drying unit 63 are temporarily retracted to a position where they do not come into contact with the thermal head unit. Move towards.

  9B, the thermal transfer layer of the thermal transfer ribbon pressed by the thermal head 44-2 on the platen roll 47 using the thermal head 44-2 and a thermal transfer ribbon (not shown) is the transfer medium. In this state, the image is written on an intermediate transfer film (not shown). The thermal head 44-3 has already been cleaned by the ultrasonic cleaning unit 62, dried by the drying unit 63, and moisture on the surface of the thermal head has been removed. Furthermore, the thermal head 44-1 is in a cleaning standby state by the ultrasonic cleaning unit 62, and is cleaned immediately before the state 3 in FIG.

  The transition from the state 2 in FIG. 9B to the state 3 in FIG. 9C is performed by rotating the central axis 65 of the columnar main body 64 as the rotation axis in the same manner as described above.

  9C, the thermal transfer layer of the thermal transfer ribbon pressed by the thermal head 44-3 on the platen roll 47 is transferred and transferred using the thermal head 44-3 and a thermal transfer ribbon (not shown). In this state, an image is written on an intermediate transfer film (not shown) as a medium. The thermal head 44-1 has already been cleaned by the ultrasonic cleaning unit 62, dried by the drying unit 63, and the moisture on the surface of the thermal head has been removed. Furthermore, the thermal head 44-2 is in a cleaning standby state by the ultrasonic cleaning unit 62, and is cleaned immediately before the state 1 in FIG.

  In the embodiment of the present invention, as shown in FIG. 6, the ultrasonic cleaning unit 62 and the drying unit 65 face the platen roll 47 with respect to the thermal head 44-1, the thermal head 44-2, and the thermal head 44-3. However, the present invention is not limited to this. For example, in this embodiment with three thermal heads, as shown in FIG. 10A, the thermal immediately before the platen roll 47 is arranged. The ultrasonic cleaning unit 62 and the drying unit 65 are arranged in this order from the position close to the thermal head 44-2 at the head position (the position facing the thermal head 44-2 in FIG. 10A). After cleaning by the cleaning unit 62, the ultrasonic cleaning unit 62 may be retracted, and instead the drying unit 63 may approach the thermal head 44-2 and dry the thermal head 44-2. Alternatively, as shown in FIG. 10B, the thermal head 44 is at a position where the rotation angle of the thermal head unit different from the transfer state is maintained (a position rotated further 30 degrees to the left in the transfer state in FIG. 10B). The ultrasonic cleaning unit 62 and the drying unit 63 are arranged in this order from a position close to -2, and after cleaning by the ultrasonic cleaning unit 62, the ultrasonic cleaning unit 62 is retracted, and instead the drying unit 63 is used as a thermal head. The thermal head 44-2 may be dried by approaching 44-2. The arrangement of the ultrasonic cleaning unit 62 and the drying unit 63 is sufficient if ultrasonic cleaning and drying can be performed in this order for the thermal head used for the next transfer, and the best arrangement can be adopted as appropriate. .

  FIG. 11 is a view showing the position of the thermal head provided in the thermal head unit in the image forming apparatus according to the present invention. FIG. 11A and FIG. 11B both show a perspective view and a plan view. The thermal head unit 70 in FIG. 11A includes a thermal head composed of three columnar main bodies 71 and three thermal heads 73, and the thermal head 73 is provided on a side surface of the columnar main body. The center axis 72 is rotated around the rotation axis. On the other hand, the thermal head unit 80 in FIG. 11B includes a thermal head composed of three columnar body portions 81 and three thermal heads 83, and the thermal head 83 has an upper surface or a bottom surface (see FIG. 11B). ) Shows the upper surface), and rotates around the central axis 82 of the columnar body 81 as the rotation axis. The position of the thermal head can be selected as appropriate.

  The thermal head unit described above has been described with respect to an image forming apparatus that includes a columnar main body and a thermal head, and has a rotation mechanism that rotates with the central axis of the columnar main body serving as a rotation axis. Next, examples of units will be described.

  FIG. 12 shows an example of another thermal head unit. The thermal head unit 90 includes a flat plate-shaped main body 91, a thermal head 92-1, and a thermal head 92-2. The thermal head unit 90 is provided with a slide mechanism (not shown). Slide.

  Further, in the vicinity of the thermal head unit 90, there are an ultrasonic cleaning section 93-1, an ultrasonic cleaning section 93-2, a drying section 94-1 and a drying section 94-2 with a platen roll 95 interposed therebetween.

  Next, operations of the thermal head unit 90, the ultrasonic cleaning unit 93-1, the ultrasonic cleaning unit 93-2, the drying unit 94-1 and the drying unit 94-2 in FIG. 12 will be described with reference to FIG. State 1 in FIG. 13A shows that the transfer layer of the thermal transfer ribbon pressed by the thermal head 92-1 on the platen roll 95 using the thermal head 92-1 and a thermal transfer ribbon (not shown) is a transfer medium. The state transferred to an intermediate transfer film (not shown) is shown. The thermal head 92-2 is cleaned by the ultrasonic cleaning section 93-2. After cleaning the thermal head 92-2, the ultrasonic cleaning unit 93-2 moves horizontally in the direction perpendicular to the paper surface. Instead, the drying unit 94-2 rises to the position of the ultrasonic cleaning unit, and the thermal head 92-2. Remove moisture from the surface.

  Transition from the state 1 in FIG. 13A to the state 2 in FIG. 13B is performed by sliding in the direction of the arrow 97 by a slide mechanism (not shown) provided in the thermal head unit 90. After the transition to the state 2 in FIG. 13B, the drying unit 94-2 moves horizontally in the direction perpendicular to the paper surface. Instead, the ultrasonic cleaning unit 93-2 rises to the position of the drying unit, and the next ultrasonic cleaning is performed. It becomes the waiting state for.

  In the state 2 of FIG. 13B, the thermal transfer layer of the thermal transfer ribbon (not shown) pressed on the platen roll 95 by the thermal head 92-2 contacts the intermediate transfer film (not shown), and the transfer layer is transferred. The thermal head 92-1 is cleaned by the ultrasonic cleaning section 93-1. After cleaning the thermal head 92-1, the ultrasonic cleaning section 93-1 moves horizontally in the direction perpendicular to the paper surface. Instead, the drying section 94-1 rises to the position of the ultrasonic cleaning section, and the thermal head 92-1. The surface moisture has been removed. In addition, the conventional machine control mechanism is appropriately employed for the replacement of the ultrasonic cleaning section 93-2 and the drying section 94-2 and the replacement of the ultrasonic cleaning section 93-1 and the drying section 94-1. I can do it.

Transition from the state 2 in FIG. 13B to the state 1 in FIG. 13A is performed by sliding in the direction of arrow 98 by a slide mechanism (not shown) provided in the thermal head unit 90. After the transition to the state 1 in FIG. 13A, the drying unit 94-1 moves horizontally in the direction perpendicular to the paper surface. Instead, the ultrasonic cleaning unit 93-1 rises to the position of the drying unit, and the next ultrasonic wave It will be in the waiting state for washing.

  The thermal head unit 90 includes two thermal heads 92-1 and 92-2. However, the number is not limited to this number, and one or more thermal heads may be appropriately employed. For example, FIG. 14 shows a case where there are three thermal heads. The thermal head unit 100 includes three thermal heads 102-1, 102-2, and 102-3, and has a slide mechanism that slides in the direction of an arrow 106. Further, in the vicinity of the thermal head unit 100, there are ultrasonic cleaning units 103-1 and 103-2 which are ultrasonic cleaning means and drying units 104-1 and 104-2 which are drying means with a platen roll 105 interposed therebetween. Has been. By increasing the number of thermal heads, the effect of extending the replacement time of the thermal head unit 100 can be expected.

  The image forming apparatus according to the present invention has been described as an embodiment of the present invention using an intermediate transfer system as an example. Next, an embodiment of the image forming apparatus according to the present invention will be described using a direct transfer system as an example.

  FIG. 15 is a schematic view for explaining the image forming apparatus according to the present invention by taking a direct transfer system as an example. The thermal transfer ribbon 111 is supplied from a ribbon unwinding roll 112, passes through a roller 113, and then pressed from the thermal transfer substrate surface of the thermal transfer ribbon 111 by a thermal head 124-1. The printing paper 115 as a transfer medium is supplied from the printing paper unwinding roll 116, transferred through the roll 114, and comes into contact with the thermal transfer layer of the thermal transfer ribbon 111 pressed on the platen roll 117, so that the transfer layer is transferred to the printing paper 115. Thus, an image is formed. Note that the printing paper 115 is not limited to a winding paper but may be a sheet. After the printing, the thermal transfer ribbon 118 passes through the roll 119 and is then taken up by the ribbon take-up roll 120. The thermal head section is composed of three thermal heads, thermal heads 124-1, 124-2, and 124-3. The thermal head unit 121 includes a columnar main body 126, a thermal head 124-1, a thermal head 124-2, and a thermal head 124-3, and a rotation mechanism that rotates with the central axis 127 of the columnar main body 126 as a rotation axis. It has. The position of the thermal head 124-1, the thermal head 124-2, and the thermal head 124-3 can be changed by the rotation mechanism. After the transfer of one screen is completed and before the transfer of the next screen is started, either the platen roll 117 or the thermal head unit 121 is moved to increase the distance between the platen roll 117 and the thermal head unit 121. The thermal head unit 121 is rotated by the rotation mechanism. Further, in the vicinity of the thermal head unit 121, an ultrasonic cleaning unit 122 that is an ultrasonic cleaning unit for cleaning the thermal head and a drying unit 123 that is a drying unit are provided.

  As in the case of the indirect transfer method, in the case of the direct transfer method, the number of thermal heads is not limited to the three as shown in FIG. 15, but is shown in FIGS. 7 (a) and 7 (b). For example, the number may be four or six, and the arrangement of the ultrasonic cleaning unit and the drying unit is not limited to the case as shown in FIG. 15 and is shown in FIGS. 9 (a) and 9 (b). Such an arrangement can also be adopted. Further, the main body of the thermal head unit can adopt either a polygonal shape or a cylindrical shape.

  Also in the direct transfer system, a thermal head unit 90 provided with a slide mechanism as shown in FIG. 12, ultrasonic cleaning units 93-1, 93-2, and drying units 94-1, 94-2 can also be employed.

As described above, according to the image forming apparatus of the present invention, by performing ultrasonic cleaning without providing a cleaning agent layer on the thermal transfer ribbon, the cloth or the like does not directly contact the thermal head. There is no adhesion, and it is also possible to remove foreign matter stuck to the thermal head and foreign matter clogged in the details of the thermal head surface. Furthermore, since a plurality of thermal heads are provided, printing can be performed by the other thermal head even when one is being washed, and therefore printing is not stopped by washing, so that a reduction in printing efficiency can be prevented. Further, by regularly cleaning the head, foreign matter can be prevented from being accumulated, and the defective rate of print recording can be reduced. Also, the replacement time of the thermal head unit can be extended by increasing the number of thermal heads.

DESCRIPTION OF SYMBOLS 1 ... Thermal transfer ribbon 2 ... Ribbon base material 3 ... Thermal transfer layer 4 ... Cleaning agent layer 5 ... Cleaning ribbon 11 ... Thermal transfer ribbon 12 ... Ribbon unwinding roll 13 ...・ Roller 13
14 ... Thermal head 14
15: Printing paper 16: Printing paper unwinding roll 1
17 ... Platen roll 18 ... Roll 19 ... Thermal transfer ribbon 20 after transfer ... Ribbon take-up roll 21 ... Thermal transfer ribbon 22 ... Ribbon unwind roll 23 ... Roller 24 ... Thermal head 25 ... Printing paper 26 ... Printing paper unwinding roll 27 ... Platen roll 28 ... Roll 29 ... Thermal transfer ribbon 30 after transfer ... Thermal transfer ribbon winding Roll 31 ... Intermediate transfer film 32 ... Intermediate transfer film unwinding roll 33 ... Roller 34 ... Secondary transfer section 35 ... Roller 36 ... Roller 37 ... Roller 38 ... Roller 39 ... Intermediate transfer film 40 after being transferred ... Winding roll 41 ... Thermal transfer ribbon 42 ... Ribbon unwinding roll 43 ... Roller 44-1 ... Thermal head 44-2 ... Thermal head 44-3 ... Thermal head 45 ... Printing paper 46 ... Printing paper unwinding roll 47 ... Platen roll 48 ... Roll 49 ... Transferred Rear thermal transfer ribbon 50 ... thermal transfer ribbon take-up roll 51 ... intermediate transfer film 52 ... intermediate transfer film unwind roll 53 ... roller 54 ... secondary transfer section 55 ... roller 56 .. Roller 57... Roller 58... Intermediate transfer film 59... Intermediate transfer film take-up roll 60. Thermal head peripheral portion 61... Thermal head unit 62. ..Drying part 64... Columnar body part 64-2. Columnar body part 64-3. Columnar body part 65.・Central axis 66... Thermal head unit 67-1, 67-2, 67-3, 67-4 ... thermal head 68 ... thermal head unit 69-1, 69-2, 69-3, 69- 4, 69-5, 69-6 ... thermal head 70 ... thermal head unit 71 ... columnar body 72 ... central axis 73 ... thermal head 80 ... thermal head unit 81 ··· Columnar body portion 82 ··· Center axis 83 · · · Thermal head 90 · · · Thermal head unit 91 · · · Plate-like body portions 92-1 and 92-2 · · · Thermal head 93-1 .... Ultrasonic cleaning section 93-2 ... Ultrasonic cleaning section 94-1 ... Drying section 94-2 ... Drying section 95 ... Platen roll 96 ... Arrow direction 97 ... Arrow direction 98 ... direction of arrow 100 ..Thermal head unit 101... Flat body portions 102-1, 102-2, 102-3... Thermal head 103-1. 104-1 ... drying section 104-2 ... drying section 105 ... platen roll 106 ... arrow 111 ... thermal transfer ribbon 112 ... ribbon unwinding roll 113 ... roller 114 ... Roller 115 ... Printing paper 116 ... Printing paper unwinding roll 117 ... Platen roll 118 ... Thermal transfer ribbon 119 after printing ... Roll 120 ... Ribbon winding roll 121 ... Thermal head unit 122 ... ultrasonic cleaning part 123 ... drying parts 124-1, 124-2, 124-3 ... thermal head 126 ... columnar main body 127 ..Central axis 130 ... thermal head units 131-1, 131-2, 131-3, 131-4, 131-5, 131-6 ... thermal head 132 ... the cylindrical shape of the thermal head unit Main body 133 ... central axis

Claims (4)

  At least means for transferring the transfer medium and image writing means for forming an image on the transfer medium using one or more thermal heads and a thermal transfer ribbon. The thermal head is provided in the thermal head unit, and the thermal head unit is in the vicinity of the thermal head unit. An image forming apparatus comprising an ultrasonic cleaning means for cleaning the head, and the thermal head unit including a movable mechanism for moving the thermal head to the ultrasonic cleaning means.   The image forming apparatus according to claim 1, further comprising a drying unit that dries the cleaned thermal head in the vicinity of the thermal head unit, and the movable mechanism moves the cleaned thermal head to the drying unit.   The thermal head unit comprises a columnar main body and a thermal head provided in the main body, and the movable mechanism is a rotating mechanism that rotates about the central axis of the columnar main body as a rotation axis. 2. The image forming apparatus according to 2.   3. The image forming apparatus according to claim 1, wherein the thermal head unit includes a flat main body and a thermal head provided in the main body, and the movable mechanism is a slide mechanism that slides the thermal head unit. .

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