JP2003320697A - Color thermosensitive printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent electrostatic attraction of dusts on a transparent part for passage of a fixing ultraviolet ray. <P>SOLUTION: A shutter plate 31 is provided removably between an upper guide member 24 with a transparent plate 33 fitted, and an optically fixing unit 32. The shutter plate 31 is made of a metal such as an iron. The lower surface of the shutter plate 31 is provided with a static eliminating brush 34 for sliding on the upper surface of the upper guide member 24. The static eliminating brush 34 made of a carbon fiber, or the like is provided longitudinally in the widthwise direction of a color thermosensitive recording paper 10 and mounted at two positions on the upstream side and the downstream side in the color thermosensitive recording paper 10 feeding direction. The shutter plate 31 is further provided with a grounding contact 35 for sliding on a metal chassis 40 of a color thermosensitive printer. While moving the shutter plate 31 between a position for opening the transparent plate 33 and a position for blocking the same, the static eliminating brush 34 eliminates the static electricity charged on the transparent plate 33. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color thermal printer, and more particularly to a color thermal printer in which a paper guide is prevented from being charged.

[0002]

2. Description of the Related Art A color thermosensitive recording paper for printing a full-color image using a color thermosensitive recording paper in which a plurality of thermosensitive coloring layers, for example, a cyan thermosensitive coloring layer, a magenta thermosensitive coloring layer, and a yellow thermosensitive coloring layer are sequentially laminated on a support. Printers are known. Usually, the yellow thermosensitive coloring layer and the magenta thermosensitive coloring layer are composed of a diazonium salt compound and a coupler which reacts with the diazonium salt compound to develop a color. The diazonium salt compound is photolyzed by irradiation with electromagnetic rays, for example, ultraviolet rays. Due to this photodecomposition, the coupler cannot react thermally, and the coloring ability of the unrecorded portion of each thermosensitive coloring layer disappears. As we all know,
This phenomenon is called light fixing. The cyan thermosensitive coloring layer contains an electron-donating precursor and an electron-accepting compound as main components, and develops a cyan color when heated.

A color thermal printer comprises a pair of transport rollers for transporting a color thermal recording paper, a thermal head for heating the color thermal recording paper to develop a color, and an optical fixing device having a lamp for irradiating ultraviolet rays. The thermal head and the optical fixing device are arranged along the conveyance direction (sub-scanning direction) of the color thermosensitive recording paper. Thermal head
While the color thermosensitive recording paper is being conveyed, the thermal recording is performed line by line in the width direction (main scanning direction) of the recording paper.

In the printing process, first, the thermal head is pressed against the recording paper to thermally record the yellow image on the yellow thermosensitive coloring layer having the highest thermal sensitivity, and immediately after that, the optical fixing device is used to record near-ultraviolet rays having an emission peak of about 420 nm. To heat-fix the yellow thermosensitive coloring layer. Next, a magenta image is thermally recorded on the magenta thermosensitive coloring layer, and then the magenta thermosensitive coloring layer is optically fixed by irradiating ultraviolet rays having an emission peak of about 365 nm. Finally, a cyan image is thermally recorded on the cyan thermosensitive coloring layer to obtain a full-color image.

The above-mentioned optical fixing device irradiates ultraviolet rays through the transparent plate fitted in the upper guide member while the recording paper is conveyed along the paper guide members arranged above and below. The paper guide member is made of an opaque plastic such as an acrylic plate, and the transparent plate is made of a transparent acrylic plate. A slidable shutter plate is arranged between the optical fixing device and the guide member, and the transparent plate is shielded by the shutter plate so that the unrecorded area following the recording area of the recording paper on which the image is recorded is not irradiated with ultraviolet rays. It is supposed to be done. This shutter plate is made of opaque plastic.

[0006]

However, the paper guide member is liable to be charged with static electricity generated by friction caused by the conveyance of the color thermosensitive recording paper or induced static electricity generated by the light emission of the optical fixing device. When the paper guide member is charged, dust and the like that have entered the printer are electrostatically adsorbed. Therefore, since the ultraviolet rays emitted from the optical fixing device are blocked by the dust attached to the transparent plate,
Uneven fixing occurs, which causes deterioration of image quality.

The present invention has been made in order to solve the above problems, and an object of the present invention is to provide a color thermal printer in which dust is prevented from adhering by removing charges from a transparent plate.

[0008]

In a color thermal printer of the present invention, a shutter plate is made of metal, and a static eliminator that is in sliding contact with a guide plate is provided on the lower surface of the shutter plate, and the shutter plate has an open position and a shield position. It is characterized in that static electricity charged in the transparent portion is removed when moving between them.

Further, it is characterized in that a grounding contact connected to the static elimination member and slidingly contacting the metal chassis is provided.

Further, the charge eliminating member is a charge eliminating brush which is elongated in the width direction of the color thermosensitive recording paper, and is provided at two positions on the upstream side and the downstream side of the shutter plate in the paper feeding direction.

[0011]

1 is a schematic view of a color thermal printer 1 according to the present invention. As the color thermosensitive recording paper, a color thermosensitive recording paper 10 in which a cyan thermosensitive coloring layer, a magenta thermosensitive coloring layer and a yellow thermosensitive coloring layer are sequentially laminated on a support is used. This color thermal recording paper 1
In the case of 0, the uppermost yellow thermosensitive coloring layer has the highest thermal sensitivity, and the lowermost cyan thermosensitive coloring layer has the lowest thermal sensitivity. Therefore, the yellow thermosensitive coloring layer develops color with low thermal energy, but a large amount of thermal energy is required to develop the cyan thermosensitive coloring layer. Further, the magenta thermosensitive coloring layer has a thermal sensitivity intermediate between that of the yellow thermosensitive coloring layer and that of the cyan thermosensitive coloring layer, and is developed by the intermediate thermal energy generated by the yellow thermosensitive coloring layer and the cyan thermosensitive coloring layer.

The yellow thermosensitive coloring layer loses its coloring ability when irradiated with near ultraviolet rays having a wavelength of 420 nm, and the magenta thermosensitive coloring layer loses its coloring ability when irradiated with ultraviolet rays having a wavelength of 365 nm.

The color thermosensitive recording paper 10 is set in the printer as a recording paper roll 11 wound into a roll. The outer peripheral surface of the recording paper roll 11 is the recording paper roll 11
A paper feed roller 12 for taking out the color thermosensitive recording paper 10 is in contact therewith. When the paper feed roller 12 is rotated clockwise by the conveyance motor 13, the recording paper roll 11 rotates counterclockwise, and the color thermosensitive recording paper 10 is sent out from the recording paper roll 11. On the other hand, when the paper feed roller 12 rotates counterclockwise, the color thermosensitive recording paper 10
Is rewound.

The recording paper roll 11 is movable toward the paper feed roller 12 and is always in contact with the paper feed roller 12 by a spring force or the like. Therefore, the color thermosensitive recording paper 10 can be reliably fed even if the winding diameter of the recording paper roll 11 becomes small.

A transport roller pair 16 composed of a capstan roller 14 and a pinch roller 15 is disposed downstream of the paper feed roller 12, and is rotated in both forward and reverse directions by a transport motor 13. The color thermosensitive recording paper 10 pulled out from the paper feeding roller 12 is sandwiched between the capstan roller 14 and the pinch roller 15, and is reciprocally conveyed in the feeding direction and the rewinding direction by the forward and reverse rotation of the capstan roller 14. To be done. The encoder 17 is attached to the rotary shaft of the capstan roller 14, and measures the amount of conveyance of the color thermosensitive recording paper 10 from the number of rotations of the capstan roller 14.

A platen roller 20 and a thermal head 21 are provided downstream of the conveying roller pair 16. The thermal head 21 has at its tip a heating element array 21a in which a plurality of heating elements are arranged in a line,
The heating element array 21a moves between a recording position where it is pressed against the color thermosensitive recording paper 10 and a non-recording position where it is retracted from the color thermosensitive recording paper 10. The thermal head 21 is
Thermal recording is performed by pressing the heating element array 21a against the recording surface of the color thermosensitive recording paper 10.

On the downstream side of the thermal head 21, an upper guide member 2 for guiding the color thermosensitive recording paper 10 being conveyed.
4 and the lower guide member 25 are provided. The upper guide member 24 and the lower guide member 25 are formed of a light-shielding material, for example, black plastic, and are fixed inside the printer so as to sandwich the conveyance path of the color thermosensitive recording paper 10. Above the upper guide member 24, a yellow ultraviolet lamp 26 and a magenta ultraviolet lamp 2 are provided.
7, a light fixing device 32 including a reflector 30 is arranged.

The yellow UV lamp 26 and the magenta UV lamp 27 are elongated rods, and those having a width larger than the width of the color thermosensitive recording paper 10 are used. The yellow ultraviolet lamp 26 emits near-ultraviolet light having an emission peak near a wavelength of 420 nm to eliminate the coloring ability of the yellow thermosensitive coloring layer. Further, the magenta ultraviolet lamp 27 emits ultraviolet light having an emission peak near a wavelength of 365 nm to eliminate the coloring ability of the magenta thermosensitive coloring layer.

The reflector 30 is provided so as to cover the yellow ultraviolet lamp 26 and the magenta ultraviolet lamp 27, and a strip-shaped opening is formed in the lower part thereof. The inner wall of the reflector 30 is a reflecting surface, and the light emitted from each ultraviolet lamp 26 or 27 is efficiently emitted downward.

As shown in FIG. 2, an opening for transmitting ultraviolet light is formed in the center of the upper guide member, and a transparent plate 33 is fitted in this opening. The transparent plate 33 is made of a transparent acrylic resin having a property of transmitting ultraviolet light and near-ultraviolet light. While passing under the transparent plate 33, the color thermosensitive recording paper 10 is irradiated with ultraviolet rays from the optical fixing device 32 to be optically fixed.

A shutter plate 31 having a light-shielding property and a conductivity is provided between the upper guide member 24 and the optical fixing device 32. The shutter plate 31 includes the upper guide member 24.
Also, it is slightly larger than the width of the lower guide member 25 and is made of metal such as iron. Further, a pair of brackets 37 is provided on both sides of the shutter plate 31, and a pair of guide shafts 38 are fitted to these brackets 37. The drive mechanism 39 includes, for example, a pinion driven by a motor and a rack formed at the lower end of the shutter plate 31, and slides the shutter plate 31 on the guide shaft 38.

Further, on the lower surface of the shutter plate 31, a brush 3 for static elimination formed by carbon fiber or the like at two locations on the upstream side and the downstream side so as to be in sliding contact with the upper surface of the upper guide member 24.
4 is attached. The static elimination brush 34 has an elongated shape in the width direction of the recording paper 10, and has a shutter plate 3
When 1 moves on the transparent plate 33, the static electricity charged on the transparent plate 31 is removed. Further, a ground contact 35 is provided on the shutter plate 31 so as to be in sliding contact with the metal chassis 40 of the color thermal printer 1, and the static electricity charged on the shutter plate 31 is discharged to the metal chassis 40 via the static elimination brush 34. To be done.

The shutter plate 31 covers the upper part of the transparent plate 33 and completely closes the ultraviolet rays from the optical fixing device 32, and moves in the rewinding direction to move the transparent plate 3 to the transparent plate 3.
The color thermosensitive recording paper 10 is moved in the conveyance direction between the open position where the color thermosensitive recording paper 10 is retracted from the upper part. The shutter plate 31 has a transparent plate 3 at the rear end of the recording area of the color thermosensitive recording paper 10.
When it is inserted into the lower part of 3, it starts moving from the open position toward the closed position. The shutter plate 31 moves at the same speed as the conveying speed of the color thermosensitive recording paper 10 so that the unrecorded portion of the color thermosensitive recording paper 10 is not irradiated with ultraviolet rays. Then, the trailing edge of the recording area of the color thermosensitive recording paper 10 reaches the closed position at the same time when it passes under the transparent plate 33, and is held in the closed position until the ultraviolet lamps 26 or 27 are extinguished.

In FIG. 1, on the downstream side of the optical fixing device 32, a fixed blade 2 arranged above the color thermosensitive recording paper 10 is provided.
2 and a movable blade 23 arranged below the color thermosensitive recording paper 10. Further, on the downstream side of the cutter, a discharge roller pair 40 including a capstan roller 36 driven by a discharge motor 35 and a pinch roller 37 pressed against the capstan roller 36 is arranged. After the end of thermal recording, the recorded color thermosensitive recording paper 10 is nipped by the pair of paper ejection rollers 40 and sent out from the ejection port 41, and when the rear end of the recording area of the color thermosensitive recording paper 10 reaches the cutter. Then, the pair of discharge rollers 40 is stopped. After that, the movable blade 23 moves upward to separate the recorded color thermosensitive recording paper 10 from the recording paper roll 11. The paper discharge roller pair 40 restarts the discharge of the recorded color thermosensitive recording paper 10 and discharges it from the color thermal printer 1 through the discharge port 41.

Next, the operation of the above embodiment will be described. When the print start operation is performed, the transport motor 13
As a result, the paper feeding roller 12 rotates and the color thermosensitive recording paper 10 is fed from the recording paper roll 11. When the color thermosensitive recording paper 10 being fed is nipped by the conveying roller pair 16,
The color thermosensitive recording paper 10 is conveyed toward the thermal head 21 by the forward rotation of the capstan roller 14. When a sensor (not shown) detects that the front end of the color thermosensitive recording paper 10 is nipped by the pair of transport rollers 16, the encoder 17 causes the capstan roller 1 to move.
The transport amount of the color thermosensitive recording paper 10 is measured from the number of rotations of 4.

The color thermosensitive recording paper 10 passes between the platen roller 20 and the thermal head 21 and is further sent out. When the carrying amount of the color thermosensitive recording paper 10 reaches a certain value, the carrying motor 13 stops and the thermal head 21 moves to the recording position. After that, the capstan roller 14 rotates in the opposite direction and conveys the color thermosensitive recording paper 10 in the rewinding direction. When the trailing edge of the recording area of the color thermosensitive recording paper 10 reaches the thermal head 21, the thermal head 21 causes the heating element array 21a to generate heat,
A yellow image is heat-recorded line by line on the yellow thermosensitive coloring layer.

When the thermal recording of the yellow image is completed, the transport motor 13 is stopped and the thermal head 21 moves to the non-recording position. After that, the capstan roller 14 rotates in the forward direction to send out the color thermosensitive recording paper 10. Further, the yellow ultraviolet lamp 26 is turned on at the same time as the sheet is conveyed in the delivery direction. Since the shutter plate 31 is held at the open position shown in FIG. 3 (A), the near-ultraviolet rays emitted from the yellow ultraviolet lamp 26 are transmitted to the transparent plate 33.
Through.

While the color thermosensitive recording paper 10 is sent out and passes under the transparent plate 33 at a constant speed, the recording area is irradiated with near ultraviolet rays and the yellow image is fixed. When the trailing edge of the recording area of the color thermosensitive recording paper 10 reaches below the transparent plate 33, the drive mechanism 39 causes the shutter plate 31 to move from the open position shown in FIG. 3 (A) to the closed position shown in FIG. 3 (B). Start moving to. Since the moving speed of the shutter is the same as the moving speed of the color thermosensitive recording paper 10, the unrecorded portion of the color thermosensitive recording paper 10 moves in a state of being overlapped with the shutter plate 31. The unusable area can be eliminated.
Further, as shown in FIG. 3 (B), since the color thermosensitive recording paper 10 is conveyed at a constant speed until the trailing edge of the recording area passes through the transparent plate 33, the entire surface of the recording area should be fixed by light. You can

When the shutter plate 31 moves from the open position to the closed position, static electricity is generated on the transparent plate 33 due to the friction of the paper passing. However, the transparent plate 33 is neutralized by the static elimination brush 34 provided on the lower surface of the shutter plate 31, and the static electricity moves to the shutter plate 31 made of metal. Further, the static electricity of the shutter plate 31 is discharged to the metal chassis 40 via the ground contact 35. Therefore, the transparent plate 33 can always discharge static electricity generated by passing the paper, and the transparent plate 33 is
It is not charged by static electricity. Therefore, since dust does not adhere to the transparent plate 33, the color thermosensitive recording paper 10 can always be irradiated with a constant light amount.

When the trailing edge of the recording area passes through the transparent plate 33 (the state shown in FIG. 3B), the transport motor 13 is stopped and the yellow ultraviolet lamp 26 is turned off. Then, the thermal head 21 moves to the recording position to sandwich the color thermal recording paper 10. The capstan roller 14 starts rotating in the opposite direction and rewinds the color thermosensitive recording paper 10. When the trailing edge of the recording area of the color thermosensitive recording paper 10 reaches the thermal head 21, the heating element array 21a generates heat to thermally record a magenta image line by line on the magenta thermosensitive coloring layer. During this time, the shutter plate 31 moves from the insertion position to the retracted position shown in FIG.

When the thermal recording of the magenta image is completed, the thermal head 21 is moved to the non-recording position and the color thermal recording paper 10 is started to be fed out. At the same time, the magenta ultraviolet lamp 27 lights up, and the color thermosensitive recording paper 1
The magenta thermosensitive coloring layer of 0 is fixed. When the trailing edge of the recording area of the color thermosensitive recording paper 10 reaches below the transparent plate 33, the shutter plate 31 starts to move to the closed position with the unrecorded portion covered, as in the case of the yellow image. . At this time, the transparent plate 33 is neutralized by the static elimination brush 34 as described above.

Next, after the magenta ultraviolet lamp 27 is turned off, the color thermosensitive color recording paper 10 is rewound for the third time by the procedure described above. When the trailing edge of the recording area of the color thermosensitive recording paper 10 reaches the thermal head 21, the heating element array 21a generates heat to thermally record a cyan image line by line on the cyan thermosensitive coloring layer. During this time, the shutter plate 31 moves to the open position.

When the thermal recording of the cyan image is completed, the feeding of the color thermal recording paper 10 is restarted. The cyan thermosensitive coloring layer has a very low thermal sensitivity and does not develop color under normal storage conditions. Therefore, the cyan thermosensitive coloring layer is not optically fixed.

After the thermal recording is completed, the recorded color thermal recording paper 10 is sent out in the direction of the paper discharge roller pair 40, nipped by the paper discharge roller pair 40, and sent out from the discharge port 41 to the outside. When the trailing edge of the recording area 10 reaches the cutter, the paper discharge roller pair 40 stops. After that, the movable blade 23 moves upward to separate the recorded color thermosensitive recording paper 10 from the recording paper roll 11. The paper discharge roller pair 40 restarts the discharge of the recorded color thermosensitive recording paper 10 and discharges it from the color thermal printer 1 through the discharge port 41.

When printing is not continuously performed, the color thermosensitive recording paper 10 is rewound on the recording paper roll 11 to prevent moisture. As a result, the color thermal recording paper 10 does not deteriorate due to moisture, and a color print with an appropriate image quality can always be obtained.

In the above embodiment, the static eliminating brush 34 is provided on the upstream side and the downstream side of the lower surface of the shutter plate 31 in the feeding direction, but the static eliminating brush 34 is provided on either the upstream side or the downstream side. Is also good. A static elimination brush may be provided so as to cover the entire lower surface of the shutter plate 31. Further, a charge removing member may be provided on the shutter plate 31. In this case, the static elimination brush can discharge the induced static electricity charged by the light emission of the yellow ultraviolet lamp 26 and the magenta ultraviolet lamp 27, and it is possible to prevent dust from adhering to the lamp. It is possible to further stabilize the amount of light applied to the thermal recording paper 10.

[0037]

As described above, according to the color thermal printer of the present invention, the shutter plate is provided with the charge eliminating brush, and the recording paper is conveyed when the shutter plate moves on the transparent portion of the guide plate. Since the static electricity of the guide member generated along with it is removed, it is possible to prevent dust from adhering to the guide plate due to static electricity. As a result, it is possible to prevent the occurrence of fixing unevenness due to the adhesion of dust and ensure stable image quality. Further, the guide plate can be cleaned by the static elimination brush.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of a color thermal printer embodying the present invention.

FIG. 2 is a perspective view showing a shutter plate of the present embodiment.

FIG. 3 is an explanatory diagram showing an operation of a shutter plate.

[Explanation of symbols]

1 color thermal printer 10 color thermal recording paper 11 Recording paper roll 24 Upper guide plate 25 Lower guide plate 31 Shutter plate 33 Transparent plate 34 Static elimination brush 35 Grounding contact 40 metal chassis

Claims (3)

[Claims] 1. A long color thermosensitive recording paper having a plurality of thermosensitive coloring layers is used, while the color thermosensitive recording paper is moved, it is heated by a thermal head to record an image and a moving path of the color thermosensitive recording paper. Has a transparent portion on the guide plate forming the, through which the portion where the image is recorded is irradiated with ultraviolet rays from an ultraviolet lamp to perform optical fixing,
A color thermal printer having a shutter plate that moves at the same speed as the color thermal recording paper between a position where the transparent portion is opened and a position where the transparent portion is shielded so that the unrecorded portion of the color thermal recording paper is not irradiated with ultraviolet rays. The shutter plate is made of metal, and a static eliminator that is in sliding contact with the guide plate is provided on the lower surface of the shutter plate, and when the shutter plate moves between the open position and the shield position, the static electricity charged in the transparent portion is charged. A color thermal printer which is characterized by removing electricity. 2. The color thermal printer according to claim 1, further comprising a grounding contact which is connected to the charge eliminating member and which is in sliding contact with a metal chassis. 3. The static eliminator is a static eliminator brush that is elongated in the width direction of the color thermosensitive recording paper, and is provided at two positions on the upstream side and the downstream side of the shutter plate in the paper feeding direction. The color thermal printer according to claim 1 or 2.