JPH11263033A - Thermal transfer printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal transfer printer which can overcoat an image formation area well without forming flashes. SOLUTION: This thermal transfer printer has an ink ribbon 7 and a transfer means. A plurality of area sets each comprising a color ink formation area where Y, M and C inks are applied, a transparent ink formation area where a transparent ink is applied and an area where ink is not applied in this order are provided on a base material of the ink ribbon. The transfer means consists of a line thermal head 9 and a platen roller 12 which, while holding the ink ribbon 7 and a recording paper 15 between the platen roller and line thermal head, transfers and forms images to an image formation area of the recording paper 15 and then overcoats the recording paper with a transparent ink. The transparent ink formation area of the ink ribbon 7 is formed to include an end part at the downstream side of the image formation area. The transfer means stops power supply to the line thermal head 9 at the area of the ink ribbon 7 where no ink is applied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fusion type or sublimation type thermal transfer printer capable of performing an overcoat process, and more particularly to a mechanism for transferring a good overcoat onto a surface on which an image is recorded with color ink.

[0002]

2. Description of the Related Art There is known a so-called thermal transfer printer in which a fusible or sublimable ink on an ink ribbon is transferred to recording paper by heat using a line thermal head. In this type of printer, a plurality of heating resistor elements of the line thermal head are individually energized to control the amount of heat generated, control the amount of meltable ink and the amount of sublimable ink sublimated, and transfer the area or density of the ink to be transferred. Can be made variable. However, prints recorded with fusible inks have the disadvantage of being vulnerable to scratches, and sublimable inks are also susceptible to oils and fats such as fingerprints and plasticizers, causing fading by ultraviolet rays and re-sublimation of ink on recording paper due to heat. Therefore, in order to protect the recorded image, a transparent ink is provided on the ink ribbon as disclosed in JP-A-61-51391 in addition to the color ink for image formation. There is known a method of transferring the image onto recording paper to maintain the strength, that is, a so-called overcoat technique. When this method is used, in the case of the meltable ink, it is resistant to abrasion, and in the case of the sublimable ink, it is possible to prevent contact with oils and fats and a plasticizer, and suppress re-sublimation.
Also, fading to ultraviolet rays can be prevented by adding an ultraviolet absorbent to the transparent ink.

[0003]

However, in general, in order to transfer the overcoat stably, it is necessary to optimize the transfer heat energy at the time of transfer and to optimize the conditions for separating the recording paper and the ink ribbon after the transfer. is there. If these are not optimized, a portion where the transparent ink cannot be transferred at the start of the overcoat transfer occurs slightly, or a phenomenon (burr) that the transparent ink is partially transferred even after the overcoat is completed occurs. FIG. 6 shows a state in which the burrs are generated. In the figure, reference numeral 15 denotes a recording sheet, a portion hatched to the lower right is an image forming area, and a portion hatched to the upper right is an overcoat area. Arrow A indicates the direction of sub-scanning. After transferring and printing the image on the image forming area, overcoating is performed in the sub-scanning direction from the top to the bottom in the figure, and when the energization of the line thermal is stopped while the transparent ink for overcoating the ink ribbon is present, the overcoating is performed. Burrs 30 are generated.

In addition, in the area where the transparent ink is not transferred, in addition to the above-mentioned problems such as abrasion, the density of the lower color ink changes due to the transfer of the transparent ink. A density difference occurs in a portion where the image is not transferred. Furthermore, since gloss is generated by applying the overcoat, a difference in gloss occurs between a portion where the transparent ink is transferred and a portion where the transparent ink is not transferred, and as a result, image quality is deteriorated. On the other hand, when burrs occur, not only does discomfort occur due to the difference in gloss,
Since the burrs have a weak adhesive force with the recording paper, they peel off after the transfer is completed and scatter into the printer, and may adhere to the recording paper or the ink ribbon at the time of subsequent printing, causing image defects.

[0005] Even if the overcoat is stably transferred, registration misregistration may occur between the recording of an image using the color ink and the transfer of the overcoat.
For example, in the case of the mechanism shown in FIG. 2, the recording paper 15 is transported by the transport roller 16 and the driven roller 17, and the transport roller is driven by the stepping motor. In this case, the stepping motor is driven to rotate by the number of steps corresponding to the size of the image to be recorded in the sub-scanning direction, and after the image is recorded with the ink having the color, the stepping motor is reversed by the same number of steps. After the recording paper is fed backward, the transparent ink is transferred again. If a slip occurs between the transport roller 16 and the recording paper 15 at the time of recording or reverse feeding, the recording start position of the image with the color ink and the transfer start position of the transparent ink will be different. As a result, a portion where overcoating is not performed occurs near the recording start position or the end position of the color ink, and is detected as a density difference.

[0006]

Means for Solving the Problems The present invention has been made in view of the above-mentioned problems, and the invention according to claim 1 is directed to a “color transfer agent forming area coated with a single color or a plurality of color transfer agents,
A transparent transfer agent forming region in which a transparent transfer agent is applied on the downstream side of the color transfer agent forming region in the sub-scanning direction, and a transfer agent continuously provided on the downstream side of the transparent transfer agent forming region in the sub-scanning direction A plurality of ink ribbons are provided face-sequentially on the base material as a set of non-forming areas, and the ink ribbon and recording paper are separated by a line thermal head and a platen roller in which a plurality of heating resistance elements are arranged in the main scanning direction. An electric current is applied to the plurality of heating resistance elements while being pressed, and the ink ribbon and the recording paper are transported in the sub-scanning direction to transfer the monochromatic or multicolor transfer agent to an image forming area of the recording paper, thereby forming an image. And a transfer unit for transferring the transparent transfer agent onto the image forming area after forming the transparent transfer agent, wherein the transparent transfer agent forming area in the ink ribbon is the image forming area of the recording paper. Downstream end in the sub-scanning direction Including so formed, said transfer means thermal transfer printer was configured to stop energization of the heating resistor elements of said plurality of in said transfer Utsushizai non-formation region upon transfer of the transfer agent of the translucent light colored. "

According to a second aspect of the present invention, there is provided an image forming apparatus, wherein the transparent transfer agent forming area in the ink ribbon is formed so as to include an upstream end in the sub-scanning direction of the image forming area of the recording paper.
2. The image forming apparatus according to claim 1, wherein the transfer unit starts energizing the plurality of heating resistor elements upstream of an upstream end of the image forming area in the sub-scanning direction when transferring the transparent transfer agent. Thermal transfer printer. ”.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a thermal transfer printer according to the present invention will be described below with reference to the drawings.
FIG. 1 shows that the line thermal head 9 is a platen roller 12.
FIG. 2 is a horizontal sectional view of the thermal transfer printer showing a state in which the line thermal head 9 is slightly separated from the platen roller 12, and FIG. 3 is a horizontal sectional view of the thermal transfer printer showing a state in which the line thermal head 9 is slightly separated from the platen roller 12. FIG. 4 is a horizontal sectional view of the thermal transfer printer showing a state in which the thermal head 9 is pressed against the platen roller 12, FIG. 4 is an explanatory diagram of an ink ribbon, and FIG. 5 is an explanatory diagram of an overcoat portion of the ink ribbon.

In FIG. 1, an ink ribbon cassette 1
The storage units 4 and 5 storing the supply roll 2 and the winding roll 3 around which the ink ribbon 7 is wound, and the storage units 4 for both rolls,
It is composed of a stay 6 connecting the first and second stays 5. The stay 6 is provided with a handle (not shown) for attaching and detaching the ink ribbon cassette 1 at a predetermined position of a thermal transfer printer (hereinafter referred to as a printer). With the handle, the ink ribbon cassette 1 is held in a direction parallel to both rolls. It can be attached and detached from the insertion slot that does not. When the ink ribbon cassette 1 is mounted on the printer, the take-up roll 3 can be driven to rotate by a motor (not shown) on the printer side. Further, a torque limiter (not shown) is provided between the motor (not shown) and the winding roll 3 so that the winding of the ink ribbon 7 can be performed in accordance with the transport speed of the recording paper 15 during recording without being affected by the diameter of the winding roll. Has become possible. The ink ribbon 7 between the supply roll 2 and the take-up roll 3 is guided by a travel guide 8 provided in both roll storage portions 4 and 5, so that the travel path of the ink ribbon 7 does not change due to a change in both roll diameters. ing.

As shown in FIG. 4, the ink ribbon 7 has areas 7Y, 7M, and 7C to which yellow, magenta, and cyan inks are applied, respectively, which are arranged in the longitudinal direction in a plane-sequential manner. After the area 7C where the ink is applied, there is provided an area 7T where the transparent ink is applied. Two light opaque marks 2 are provided between the area 7Y to which the yellow ink is applied and the area 7T to which the transparent ink is applied.
4a are provided, between the area 7Y coated with yellow ink and the area 7M coated with magenta ink, between the area 7M coated with magenta ink and the area 7C coated with cyan ink, and between cyan area A single light-opaque mark 24b, 24c, 24d is provided between the area 7C where the ink is applied and the area 7T where the transparent ink is applied.
Is provided.

The line thermal head 9 is fixed to a head arm 11 about a rotation axis of the shaft 10. The line thermal head 9 is moved by an unillustrated head arm driving means to the ink ribbon cassette attaching / detaching position shown in FIG. The position can be moved to the ink ribbon positioning position shown in FIG. 3 and the line thermal head pressure bonding position shown in FIG. An ink ribbon guide 13 is fixed to the leading end of the line thermal head 9 on the take-up roll 3 side.
The position where the recording paper 15 and the ink ribbon 7 are separated is defined. An ink ribbon sensor 14 composed of a reflection type optical sensor is fixed to the ink ribbon guide 13, and the light emitting portion and the light receiving portion are arranged in a row of the heating resistor elements of the line thermal head 9 (in a direction perpendicular to the paper at a position 9b in the drawing). Are arranged in a parallel direction.

Platen roller 1 whose surface is made of an elastic member
Numeral 2 is rotatably supported between frames of the printer. During recording, the line thermal head 9 presses both the ink ribbon 7 and the recording paper 15 against the platen roller 12 so that the ink ribbon 7 is moved to the recording paper 15. In close contact. The recording paper transport roller 1 is located on the upstream side of the platen roller 12 in the sub-scanning direction (left side in the figure, hereinafter, this direction is simply called “upstream side” and the opposite direction is simply called “downstream side”).
6 is rotatably supported between frames of the printer, and an output shaft of a stepping motor (not shown) is directly connected to the recording paper transport roller 16 via a speed reduction mechanism. Therefore, the recording paper transport roller 16 is driven to rotate forward and backward freely by the rotation control of the stepping motor.
For example, the recording pitch for one line by the line thermal head 9 is 175 μm, the length of the image forming area on the recording paper 15 in the sub-scanning direction is 112 mm, and a stepping motor is used to transport the recording paper 15 for one line. If it is rotated by the step, a maximum of 640 lines can be recorded on the recording paper 15, and the stepping motor may be rotated by 2560 steps.

A driven roller 17 made of a metal material is provided above the recording paper transport roller 16, and an elastic member (not shown) presses the driven roller 17 against the recording paper transport roller 16. Guide plates 18 and 19 are fixed to the frame of the printer on the upstream side of the recording paper transport roller 16, and these guide plates 18 and 19 are connected to the recording paper 15 fed to the paper feed port 21 by means not shown. Guide me,
The recording paper 15 is guided between the recording paper transport roller 16 and the driven roller 17, and the recording paper 15 being recorded is also guided by the guide plates 18 and 19 in the direction of the paper supply / discharge port 21. A reflection type optical sensor 20 is provided between the recording paper transport roller 16 and the guide plate 19, and the paper supply / discharge port 2 is provided.
The front end or the rear end of the recording paper 15 conveyed from 1 or the recording paper 15 conveyed by the recording paper conveyance roller 16 and the driven roller 17 are detected.

Next, the operation of the printer having such a configuration will be described with reference to FIGS. FIG. 1 shows a state in which the line thermal head 9 is separated from the platen roller 12, for example, in a standby state before recording, when the ink ribbon cassette 1 is attached or detached, and the like. When recording is started from this state, the head arm 11 supporting the line thermal head 9 is rotated counterclockwise around the axis 10 by a head arm driving means (not shown), and the line thermal head 9 moves to the position shown in FIG. . At this time, the ink ribbon sensor 14 is close to the driven roller 17, and the arrangement of the light emitting and receiving portions of the ink ribbon sensor 14 is
The light-emitting and light-receiving surfaces are parallel to the axial direction of FIG. On the other hand, the conveyance path of the ink ribbon 7 is changed by the ink ribbon guide 13 and moves to a position where the ink ribbon 7 comes into contact with the driven roller 17.

In this state, when the take-up roll 3 is rotated counterclockwise in FIG. 2 by means (not shown), the ink ribbon 7 moves to start positioning the yellow color, which is the first color. Since the ink of each color has a property of transmitting with respect to the emission wavelength of the ink ribbon sensor 14, the light emitted from the light emitting unit passes through the ink ribbon 7 and reaches the driven roller 17, and the driven roller 17 is made of metal. Therefore, the light is reflected, passes through the ink ribbon 7 again, and returns to the light receiving portion. Since only the yellow mark 24a is two, the first mark is detected, the transparent portion is reached again, and when the second mark is detected, the rotation of the winding roll 3 is stopped. At this time, time measurement is started from when the transparent portion is reached, and if the second mark can be detected within a predetermined time, it is determined that the mark is for yellow. With such processing, no mark of another color is detected when the yellow color is located.

When two yellow marks are detected and the feeding of the ink ribbon 7 is stopped, the recording paper 15 is conveyed from the paper supply / discharge port 21 by means not shown.
When the leading end of the recording paper 15 reaches just before the interval between the recording paper transport roller 16 and the driven roller 17, this is detected by the reflection type optical sensor 20, and the recording paper transport roller 16 is driven by a stepping motor (not shown) to rotate clockwise. Start spinning. In this state, the leading end of the recording paper 15 is further
When the recording paper 15 reaches between the roller 6 and the driven roller 17, the recording paper 15 is conveyed by the recording paper conveying roller 16 and the driven roller 17. The leading end of the recording paper 15 passes between the platen roller 12 and the line thermal head 9 and is bent downward by the recording paper guide 9 a on the line thermal head 9.
Further, it is guided between the storage section 4 of the supply roll 2 of the ribbon cassette 1 and the printer lower frame 23. At this time, the recording paper 1
5 is detected by the reflection type optical sensor 20, the predetermined number of lines (the number of steps of the stepping motor), for example, 50 lines, are recorded within a range where the recording paper 15 does not fall out between the recording paper transport roller 16 and the driven roller 17. The paper transport roller 16 is further rotated and stopped.

When the recording paper 15 is conveyed to this position, the line thermal head 9 is pressed against the platen roller 12 by head arm driving means (not shown) (FIG. 3). In this state, the ink ribbon 7 is taken up by the take-up roll 3 while rotating the recording paper transport roller 16 in the counterclockwise direction to feed the recording paper in the direction of the paper supply / discharge port 21. The rear end of the recording paper 15 (the front end in the recording direction) is again reflected by the reflection type optical sensor 20.
When the detection is made, the energization of the line thermal head 9 is started. Thereafter, the yellow ink on the ink ribbon 7 is transferred to the recording paper 15 by performing a predetermined energization for each line. For example, as described above, if the recording pitch for one line of the line thermal head is 175 μm and the length of the image forming area on the recording paper 15 is 112 mm,
Recording of 640 lines is performed on the recording paper 15. At this time, if the stepping motor is rotated by four steps to convey the recording paper 15 by one line, the stepping motor may be rotated by 2560 steps. When the recording of 640 lines is completed, the recording paper 15 is conveyed without energizing the line thermal head 9 for a predetermined number of lines (for example, five lines) in order to cool the line thermal head 9. The winding of the winding roll 3 of the ink ribbon cassette 1 is stopped.

Next, after the line thermal head 9 is separated by means (not shown) as shown in FIG. 2, the winding roll 3 of the ink ribbon cassette 1 is wound again to detect the magenta ink mark 24b. This is performed by the ribbon sensor 14. In this case, since the recording of yellow has been completed, the mark 24b detected first is determined to be for magenta ink, and the winding of the winding roll 3 is stopped. Next, the recording paper transport roller 16 is rotated clockwise to return the recording paper 15. As before, when the rear end of the recording paper 15 is detected by the reflection type optical sensor 20, a predetermined number of lines (for example, 50 lines) are provided within a range where the recording paper 15 does not fall out between the recording paper transport roller 16 and the driven roller 17. The recording paper transport roller 16 is further rotated and stopped.

In the same manner as when recording the yellow ink, the line thermal head 9 is pressed against the platen roller 12 by a head arm driving means (not shown), and the recording paper transport roller 16 is rotated counterclockwise to transport the recording paper 15. The ink ribbon 7 is taken up by the take-up roll 3 while being fed in the direction of the paper supply / discharge port 21. When the rear end (which is the leading end in the recording direction) of the recording paper 15 is detected again by the reflection type optical sensor 20, the line thermal head 9 is energized, and thereafter the predetermined energization is performed for each line. Then, the magenta ink on the ink ribbon 7 is transferred to the recording paper 15. As described above, when printing 640 lines on the recording paper 15,
Further, the recording paper 15 is transported without energizing the line thermal head 8 for a predetermined number of lines (for example, five lines), and the rotation of the recording paper transport roller 16 and the winding of the winding roll 3 of the ink ribbon cassette 1 are stopped. Then, similarly, the line thermal head 9 is separated from the platen roller 12, and the mark 24c of the cyan ink is detected. In this case, since the recording of magenta has been completed, the first detected mark 24c is determined to be for cyan ink, and the winding of the winding roll 3 is stopped.

Next, the recording paper transport roller 16 is rotated clockwise to return the recording paper 15. As before, when the rear end of the recording paper 15 is detected by the reflection type optical sensor 20, a predetermined number of lines (for example, 50 lines) are provided within a range where the recording paper 15 does not fall out between the recording paper transport roller 16 and the driven roller 17. The recording paper transport roller 16 is further rotated and stopped. again,
The line thermal head 9 is pressed against the platen roller 12 by a head arm driving means (not shown), and the recording paper transport roller 16 is rotated in a counterclockwise direction to feed the recording paper 15 to the paper supply / discharge port 2.
While feeding the ink ribbon 7 in the direction 1, the ink ribbon 7 is wound up by the winding roll 3. When the rear end (the leading end in the recording direction) of the recording paper 15 is detected again by the reflection type optical sensor 20, the energization of the line thermal head 9 is started, and thereafter, the predetermined energization is performed for each line. Thus, the cyan ink on the ink ribbon 7 is transferred to the recording paper 15. As described above, when 640 lines are recorded on the recording paper 15, the recording paper 15 is further conveyed without energizing the thermal head 9 for a predetermined number of lines (for example, 5 lines). The rotation and the winding of the winding roll 3 of the ink ribbon cassette 1 are stopped. Thus, the three color inks are superimposed on the recording paper, and the color recording is completed.
Next, overcoat transfer is performed.

First, after the line thermal head 9 is separated by the head arm driving means as shown in FIG.
The winding roll 3 of the ink ribbon cassette 1 is wound again, and the ink ribbon sensor 14 detects the mark 24d of the transparent ink. In this case, since the recording of the cyan ink has been completed, the mark 24d detected first is determined to be for the transparent ink, and the winding of the winding roll 3 is stopped. Next, the recording paper transport roller 16 is rotated clockwise to return the recording paper 15. As before, when the rear end of the recording paper 15 is detected by the reflection type optical sensor 20, a predetermined number of lines (for example, 50 lines) are provided within a range where the recording paper 15 does not fall out between the recording paper transport roller 16 and the driven roller 17. The recording paper transport roller 16 is further rotated and stopped.

The line thermal head 9 is pressed against the platen roller 12 by the head arm driving means in the same manner as when recording the cyan ink, and the recording paper transport roller 16 is pressed.
Is rotated counterclockwise to feed the recording paper in the direction of the paper supply / discharge port 21 and wind up the ink ribbon 7 with the take-up roll 3. At this time, unlike the transfer of the yellow ink, magenta ink, and cyan ink, the rear end of the recording paper 15 (which is the front end in the recording direction) is detected again by the reflection type optical sensor 20 and then the line thermal head 9 is moved. Instead of starting the energization, the energization to the line thermal head 9 is started at the same time as the recording paper transport roller 16 is rotated in the counterclockwise direction. As a result, the transfer of the transparent ink is started from the near side (about 50 lines before) from the recording start position of the color ink. The transfer end position of the transparent ink is performed from the final transfer line position of the color ink to a position where the recording paper is further conveyed.

As shown in FIG. 5, the area 7T to which the transparent ink has been applied is a transparent ink application section 7T-1 to which the transparent ink has been applied, and is downstream of the transparent ink application section 7T-1. And a transparent ink non-applied portion 7T-2 on which the transparent ink is not applied. The area of the transparent ink application portion 7T-1 is the mark 2 for the transparent ink.
L1 + ΔL + L2 + L3 or more L1 + L2 from the tip of 4d
+ L3 + L4 or less (however, ΔL <L3). Here, L1 is a mark 24 for transparent ink.
d is the length from the leading end to the position where the leading line of the transparent ink is transferred, and is theoretically the length of the ink ribbon travel path from the ink ribbon sensor 14 to the heating resistor element position 9b of the line thermal head 9 in the state of FIG. However, in reality, even if the ink ribbon sensor 14 detects the mark and stops supplying power to the motor that drives the take-up roll 3, the take-up roll 3, the motor, and the like further wind the winding.
Therefore, there is a stop position error ΔL that occurs due to a take-up roll diameter, a take-up load, a difference in printer body, and the like.

As described above, L2 is detected by the reflection type optical sensor 20 at the rear end of the recording paper 15, and further recording is performed within a range where the recording paper 15 does not fall out between the recording paper transport roller 16 and the driven roller 17. A predetermined number of lines for transporting the paper 15 (for example, 50
L3 is the length in the sub-scanning direction of the image forming area for transferring the color ink (for example, 640 lines)
And L4 is a length for transferring the transparent ink to the recording paper further than the final transfer line position of the color ink. Therefore, if the length from the final transfer position of the color ink to the final transfer position of the transparent ink is set to the number of lines that is equal to or more than ΔL, the transfer of the transparent ink ends during the energization of the line thermal head 9. Will do. Further, the application area of the transparent ink does not end before (upstream side) the final transfer position of the color ink. That is, in this printer, when the transparent ink is transferred, the line thermal head 9 is used.
The stop of the power supply is performed in the transparent ink non-application portion 7T-2 where the transparent ink is not applied. Therefore, burrs do not occur at the transfer end portion of the transparent ink.

When the energization of the line thermal head 9 is completed, the driving of the recording paper transport roller 16 is stopped, the line thermal head 9 is separated from the platen roller 12, and the winding of the winding roll 3 is also stopped. Thereafter, the recording paper transport roller 16 is again rotated counterclockwise to
Is completely separated from the recording paper transport roller 16 and the driven roller 17, and the recording paper 15 is discharged out of the printer from the paper supply / discharge port 21 by means not shown. Then, the reflection type optical sensor 20
When the recording paper 15 is no longer detected,
Stop the rotation of. Although the printer described here has been described with respect to the case where color printing is performed using yellow, magenta, and cyan inks and overcoating is performed, the overcoating operation is the same even when recording is performed using a single color ink.

[0026]

According to the present invention, the overcoat transfer is performed before the recording start position by the color ink, the overcoat transfer is further performed from the recording end position, and the heat generation resistance of the line thermal head is formed in the transfer agent non-forming area. Since the power supply to the element is stopped, there is no overcoat defect area near the start or end of recording due to registration error. In addition, even if a portion where the transparent ink cannot be transferred occurs at the start of the overcoat transfer, an overcoat transfer failure region does not occur in the image forming area, causing image quality failure due to a density difference or a portion having poor weather resistance. Nothing to do. Then, since the transparent ink application area is completed while the overcoat transfer is being performed further from the recording end position of the color ink, no burrs of the transparent ink occur,
In addition to obtaining visually good image quality, it is possible to prevent the transparent ink from scattering inside the printer and to prevent image defects due to the transparent ink.

[Brief description of the drawings]

FIG. 1 is a horizontal sectional view of a thermal transfer printer showing a state where a line thermal head is separated from a platen roller.

FIG. 2 is a horizontal sectional view of the thermal transfer printer showing a state where the line thermal head is slightly separated from a platen roller.

FIG. 3 is a horizontal sectional view of the thermal transfer printer showing a state in which the line thermal head is pressed against a platen roller during image recording.

FIG. 4 is an explanatory diagram of an ink ribbon.

FIG. 5 is an explanatory diagram of an overcoat portion of the ink ribbon.

FIG. 6 is an explanatory diagram of burrs at an overcoat end portion generated when overcoating is performed by a conventional thermal transfer printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink ribbon cassette 2 Supply roll 3 Winding roll 4 Storage part 5 Storage part 6 Stay 7 Ink ribbon 8 Travel guide 9 Line thermal head 10 Axis 11 Head arm 12 Platen roller 13 Ink ribbon guide 14 Ink ribbon sensor 15 Recording paper 16 Recording paper Conveyance roller 17 Follower roller 18 Guide plate 19 Guide plate 20 Reflective optical sensor 21 Paper supply / discharge port 23 Lower frame 24 Mark 30 Burr

Claims (2)

[Claims] An image forming apparatus includes: a color transfer agent forming region coated with a transfer agent of a single color or a plurality of colors; a transparent transfer agent formed region coated with a transparent color transfer agent on a downstream side of the color transfer agent forming region in a sub-scanning direction. ,
A plurality of ink ribbons provided in a sub-scanning direction on the substrate as a set of a transfer agent non-forming region continuously provided on the downstream side of the transparent transfer agent forming region, and a plurality of ink ribbons provided in the main scanning direction. The plurality of heating resistance elements are energized while pressing the ink ribbon and the recording paper with a line thermal head and a platen roller in which the heating resistance elements are arranged, and the ink ribbon and the recording paper are conveyed in the sub-scanning direction. Transfer means for transferring the transfer agent of one or more colors to an image forming area of the recording paper to form an image, and then transferring the transparent transfer agent on the image forming area. The transparent transfer agent forming area of the ink ribbon is formed so as to include a downstream end in the sub-scanning direction of the image forming area of the recording paper, and the transfer unit transfers the transparent transfer agent. When the transfer agent is not formed, Configuration and the thermal transfer printer to stop the energization of the heating resistor element. 2. The image forming apparatus according to claim 1, wherein the transparent transfer agent forming area in the ink ribbon is formed to include an upstream end of the image forming area in the sub-scanning direction of the recording paper. 2. The thermal transfer printer according to claim 1, wherein upon transfer of the agent, the plurality of heating resistor elements are started to be energized upstream of an upstream end of the image forming area in the sub-scanning direction.