JPH1044540A - Thermal printer equipped with improved print head assembly, recirculator for receiver, sheet carrier for dye donor web and receiver sheet sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop a printer requiring no large drum in which a receiver sheet is not required to reverse the moving direction after passing through a print path by recirculating the receiver sheet in a closed loop. SOLUTION: When a press contact roller 18 turns counter clockwise and a receiver sheet 22 is present, the receiver sheet 22 is discharged through an insertion/discharge port. Subsequently, a head 30 moves onto a platen 34 and the press contact roller 18 moves onto a guide wall part 14. When a new receiver sheet 22 is inserted into the path 12, it is detected by a sensor 44. Subsequently, the print head 30 is preheated and lowered until a dye donor web 31 is press fitted to a nip between the print head 30 and the platen 34. When a last print path is completed, the press contact roller 18 is coupled with the receiver sheet 22 and turned counter clockwise thus discharging a printed matter from a thermal printer 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thermal printer in which a printhead engages and selectively heats a die donor web to transfer a die to a receiver sheet. More specifically, the present invention provides a printhead with improved features for engaging the printhead with the die donor web during printing; recirculating the receiver sheet in the printing direction during the printing pass. A printer that uses a printing platen to move the dye donor web during successive printing passes; to generate a signal indicating that the receiver sheet is set in the correct position for printing; The present invention relates to a printer in which a front edge of a receiver sheet engages a sensor and activates the sensor.

[0002]

2. Description of the Related Art The printing process of a thermal printer involves the sequential execution of various mechanical and electromechanical operations. For example, one die receiver, or receiver sheet, must be loaded into a printer and positioned exactly in the print zone. The dye donor web, along with the receiver sheet, must be accurately located in the print zone of the register. The printhead must move to form a print nip with the rotatable platen, and the receiver sheet and die donor web are sandwiched between the printhead and the platen. The receiver sheet and die donor web must be accurately conveyed through the printing nip. The above operations have to be repeated according to the number of colors used in the finished print. Finally, when the print is printed on the receiver sheet, the print must be ejected from the printer.

[0003]

Although the above thermal printing method may vary slightly depending on the design of the printer, all printers have a mechanism for performing a particular print cycle and a properly programmed controller. Having both. The cost of the mechanism is higher than the cost of the software for the controller, so to reduce the cost of manufacturing the printer, it is necessary to minimize the number of mechanical and electromechanical hardware of the printer. While it is important to simplify printer design, most commercial thermal printers have a first dedicated electromechanical system to transport the receiver sheet through the print nip and a die donor through the print nip. And a second electromechanical system for transporting the web.

[0004] US Patent No. 5,28, commonly assigned.
As described in U.S. Pat. No. 0,303, receiver sheets are usually supplied fixed to a large printing drum. Alternatively, the receiver sheet can be pulled out and sent out through a print nip by a pinch roller. The donor is usually collected on a take-up spool, which is driven by an independent motor and drive train through a clutch slip. In the case of commonly assigned patent printers,
A capstan downstream of the printhead assists in continuously applying minimal tension to the donor web during printing, and sends the donor web through the print path. Therefore, in order to manufacture thermal printers that are more readily available to a large number of customers, there is a need to reduce the number of mechanical and electromechanical systems and make their mechanisms even simpler.

[0005] In the case of thermal printers of the type described above, the print head is transferred to the die donor web and the die donor web is transferred to the receiver sheet, usually with a pressure of 5.9 kg, in order to ensure a uniform transfer of the die to the receiver sheet. And the receiver sheet must be crimped to the platen.
The mechanism for supplying the pressure must be strong enough to support the load without breaking or bending during the printing operation. In prior art printers, the printhead was typically supported by an access door rotatably supported by a pivot on the frame of the printer. A head load spring extends between the access door and the printhead so that when the door is closed, the spring contracts to apply the required pressure. In the case of such a device,
The pressure is absorbed by printer doors, door hinges or pivots, door latches and frames.
Therefore, doors, hinges and frames need to be designed more robustly than necessary, which results in higher costs but higher reliability. There is a need for a simple and reliable mechanism that can engage a printhead with an access door and its support structure without undue force.

Further, in the case of the above-mentioned printer, in order to transfer each successive die, the receiver sheet is fixed to a large drum so as to repeatedly feed the receiver sheet, and the receiver sheet is fixed. Rotate this drum in the printing direction or position the receiver sheet for the purpose of transferring the receiver die and transferring the second die while contacting the print head in the printing direction to transfer the first die To do so, a method has been adopted in which the moving direction of the receiver sheet is reversed, and then the receiver sheet is conveyed by advancing it in the printing direction in order to transfer the second die. The receiver sheet can be recirculated in a closed loop, in the printing direction, between print passes, thereby eliminating the need for large drums or reversing the direction of movement of the receiver sheet after passing through each print pass There was no printer development awaited.

Further, in the case of the above-described printers, independent mechanisms have been used to position the dye donor web between print passes. As a result, the printer has become complicated and expensive. By using a dye donor web having a continuous group of yellow, magenta and cyan dies during the printing pass for each color, a full color image could be made in a well-known manner, in this case The dye donor web had to be precisely aligned with the receiver sheet. One well-known technique for performing the above alignment is commonly assigned US Pat.
280,303 discloses a method. A color identification optical sensor is located in the donor passage upstream of the printhead to detect the beginning of each group of color patches. A dedicated transport system is used to move the dye donor web to the required position at the beginning of the printing cycle according to the output from the sensor. The use of a dedicated transport system for dye donor webs significantly increases the cost of the printer and the complexity of the mechanism. Therefore, there was a need for a simpler and cheaper way to place the dye donor web where needed.

Finally, in the case of such a printer,
At the start of printing, it is necessary to know the position of the front edge of the receiver sheet accurately. Commonly assigned U.S. Patent No. 5,
In the case of 280,303, the leading edge is fixed to a printing drum positioned by a servomotor, thereby being set in the correct position. In other known printers, the receiver sheet is pulled between the printhead by a capstan and a pinch roller, and the leading edge of the receiver sheet is detected by a sensor near the capstan. The development of a technique for accurately sensing the position of the leading edge while the receiver sheet is being fed by the rotating platen has been awaited.

[0009]

SUMMARY OF THE INVENTION It is a primary object of the present invention to provide a simpler and less costly thermal printer.

Another object of the present invention is to provide a printer capable of printing printed matter of the same quality as a photograph by a printer having a simple structure and a low cost.

It is yet another object of the present invention to provide an improved printhead assembly for a printer that can operate without undue loading of nearby printer structures.

It is yet another object of the present invention to provide an improved thermal printer that recirculates a receiver sheet in a closed loop in a printing direction to simplify the construction and operation of the printer.

Yet another object of the present invention is to feed and position the dye donor web by the same rotation of the platen used during printing, thereby eliminating the need for a separate transport system for the dye donor web. It is to provide an improved thermal printer.

Yet another object of the present invention is to provide a means activated by the leading edge of the receiver sheet being fed by the rotating platen to indicate that the receiver sheet is in the correct position for printing. , To provide an improved thermal printer.

The above objects are merely illustrative,
Those skilled in the art will be able to conceive and understand the desired objects and advantages achieved by the present invention. However, the scope of the present invention is limited only by the appended claims.

The thermal printer of the present invention comprises a rotatable platen having a set of opposed shaft ends, a printhead mounted parallel to the platen, and the printhead comprising a die donor web and a die receiver sheet. Means for holding the printhead adjacent to the platen so that the die receiver sheet can be pressed against the platen. The printer includes an elongated beam spring having opposing ends; a fulcrum member extending from the support means for engaging the beam spring between the opposing ends; and (a) thermally transferring the die to the receiver sheet. (B) sufficient when the platen is rotated to move the die donor web or both the die donor web and the die receiver sheet through between the print head and the platen, Force to cause the beam spring to bend, pressure to engage the printhead with the die donor web, engage the die donor web with the die receiver sheet, and engage the die receiver sheet with the platen. Means for engaging the beam spring at the opposite end.

The engagement means includes a set of movable cams, each having a slot for reducing the radius of the platen from the axis of rotation of the platen, and for engaging the printhead with the die donor web by pressure. , Means for moving the cam, wherein each slot engages one of the opposing ends. Each slot is open toward the perimeter of each cam so that the printhead, fulcrum member and beam spring can disengage from the cam. Support means can be pivotally mounted to the printer frame so that the printhead can easily engage and disengage with the dye donor web. The printer has a receiving housing with an access door, the support means can be connected to the access door, and the access door can be opened by rotating the support means. The access door and support means can be pivotally mounted coaxially to the printer frame. In one embodiment of the invention, the engagement means comprises a set of rotatable cams and means for rotating the cams to engage the printhead with the die donor web by pressure. In this case, each cam has a slot for reducing a radial distance from the rotation axis of the platen, and the slot is engaged with one of the opposed ends. Each plate cam can be mounted for rotation about a respective one of the shaft ends of the platen.

The thermal printer of the present invention is suitable for printing on a receiver sheet having a leading edge and a trailing edge.
A printer comprising: an elongated rotatable platen; an elongated printhead mounted parallel to the platen; at least a portion of which is located in the passage for engagement with a receiver sheet or die donor web. A closed loop path for recirculating the receiver sheet in the printing direction from and toward the platen adapted to rotate in the printing direction; supply of a die donor web located upstream of the printhead A roll; means for moving the printhead into a passage facing the platen to engage the printhead by crimping, in a manner previously described; and a die donor through the space between the printhead and the platen. To move both the web or dye donor web and die receiver sheet, Means for rotating the platen in the printing direction; and means for recirculating the receiver sheet through a closed loop passage in the printing direction for continued thermal transfer of different dies from the die donor web. it can.

The recirculation means includes roller means extending within the passage for feeding the receiver sheet through the closed loop passage in the printing direction; the leading edge of the receiver sheet being disposed between the platen and the dye donor web. And means for sensing and generating a signal as it passes through it; means for releasing the roller means from the receiver sheet according to said signal before printing commences. The platen rotating means also rotates the roller means about the shaft, the means for releasing the roller means includes a cam, the cam follower engages the cam and the shaft, and the cam moving means moves the follower and the shaft. To engage or disengage the roller means with the receiver sheet. The rotating means comprises a first pulley mounted for rotation with the platen; a second pulley mounted for rotation with the shaft and roller means;
A resilient drive belt is engaged with the first and second pulleys to transmit rotation to the roller means and maintain engagement between the cam and the cam follower. In one embodiment of the invention, the platen has a shaft with an end, the cam has a plate cam mounted for rotation about said end, and The means for rotating the cam. The roller means can be mounted on a shaft, which is positioned at an acute angle in the direction of movement of the receiver sheet through the passage.

Means for sensing when the leading edge of the receiver sheet arrives at a predetermined location downstream of the printhead and generating another signal, and in accordance with the other signal, a die donor web and a receiver. Means for operating the printhead may be provided to move the die to and from the sheet. The leading edge sensing and signal generating means includes a pivotally supported sensor lever having a free end located downstream of the printhead for engaging the leading edge of the receiver sheet; Means for sensing movement of the sensor lever when contact between the free end and the leading edge moves.

The printer includes a take-up roller located downstream of the printhead for receiving the dye donor web after passing between the printhead and the platen. The platen rotating means also rotates the take-up roll, and a platen driving member fixed on a shaft of the platen; a winding driving member rotatably mounted on the shaft of the platen; and a shaft of the platen. In addition, a slip for rotating the winding member
Clutch means; means for transmitting the rotation of the winding drive member to the winding roll. Means for preventing reverse rotation of the take-up roll may be provided.

The platen rotating means also rotates the roller means on the shaft and the means for disengaging from the roller means comprises ears projecting radially on a rotatable cam, the cam follower comprising: Engagement of the lug with the shaft, whereby rotation of one cam causes the follower and shaft to move, thereby causing the roller means to engage and disengage with the receiver sheet.

One method of the present invention is suitable for thermally printing onto a receiver sheet using a dye donor web consisting of a continuous color group of patches of different dies. The method includes: (a) engaging a thermal printhead on one side of a die donor web, engaging the other side of the die donor web on one side of a receiver sheet, and rotating the other side of the receiver sheet. Engaging with a possible platen; (b) rotating the platen in the printing direction to feed both the dye donor web and the receiver sheet; and (c) simultaneously with the step (b).
Activating the printhead to transfer the first color die of the group to the receiver sheet;
(D) after the transfer of the first color, to advance the receiver sheet between the platen and the dye donor web;
Continuously rotating the platen in the printing direction;
(E) advancing the dye donor web by a predetermined length, thereby continuing to rotate the platen in the printing direction to position the downstream of the printhead at the beginning of the next color in the color group; Then stopping the rotation of the platen; and (f) removing the printhead from the dye donor web;
(G) recirculating the receiver sheet in the printing direction and re-introducing the receiver sheet between the die donor web and the platen; (h) re-engaging the printhead with the die donor web; Re-rotating the platen in the printing direction to forward both the die donor web and the receiver sheet; and (j) transferring the next color die of the color group to the sheet simultaneously with step (i). Actuating the printhead. The method also comprises the step (k)
It comprises the steps of repeating steps (d)-(j) for subsequent colors of the color group to complete printing on the receiver sheet.

The dye donor web includes a continuous color group of patches of different dies, and the printer further senses the transition from the previous color group to the current color group and generates a signal. And means for rotating the platen according to the signal until the transition reaches a predetermined position downstream of the printhead.

Another method of the present invention is suitable for thermal printing using a dye donor web consisting of a continuous color group of patches on different dies. This method comprises the steps of (a)
A thermal printhead is applied to one side of the dye donor web,
Engaging the elongated rotatable platen and engaging the other side with the elongated thermal printhead; (b)
Rotating the platen in the printing direction to advance the dye donor web; (c) upstream of the platen and printhead, the end of the previous color group;
Sensing the transition between the tip of the current color group; and (d) advancing the dye donor web by a predetermined length after said sensing, whereby the next of the current color group is reached. Continuing to rotate the platen in the printing direction to position the color tip at a position downstream of the printhead, and then stopping rotation of the platen; (e) disengaging the printhead from the dye donor web (F) re-introducing the receiver sheet between the dye donor web and the platen after the disengagement; (g) engaging the printhead with the dye donor web and attaching the die donor web to the receiver sheet. Engaging and engaging the receiver sheet with the platen; (h) advancing both the dye donor web and the receiver sheet; Rotating the platen in the printing direction to actuate the print head to transfer the first color die of the current color group to the sheet simultaneously with (i) the j step (h). And

The other method described above further comprises: (j) continuing to rotate the platen in the printing direction after the first color transfer to advance the receiver sheet from between the platen and the dye donor web. (K) advancing the dye donor web by a predetermined length, thereby positioning the platen in the printing direction downstream of the printhead to locate the beginning of the next color in the current color group. Continuing rotation and then stopping rotation of the platen; (l) removing the printhead again from the dye donor web; and (m) reintroducing the receiver sheet between the dye donor web and the platen. (N) re-engaging the printhead with the dye donor web; (o) the dye donor web and receiver Re-rotating the platen in the print direction to advance both of the plates; (p) simultaneously with step (n) to transfer the next color die of the current color group to the receiver sheet Activating the print head. The method also includes the step (q) of repeating steps (j)-(p) for subsequent colors of the current color group to complete printing on the receiver sheet.

<Operation of the Present Invention> With reference to FIGS. 1 to 6 and the following description, those skilled in the thermal printer arts will be able to understand the overall structure and operation of the thermal printer device 10 of the present invention. Would. The closed loop passage 12 is provided with the outer guide wall 1.
4 and the inner and outer wall portions 16. Although one of ordinary skill in the art only shows one of these in FIGS. 1-6, two sets of such guide walls are provided for moving through the printer with respect to at least two opposing edges of the receiver sheet web. It can be seen that it is provided to form a passage. Of course, those skilled in the art will appreciate that passages 12 may be provided across the width of the receiver sheet to better support and guide the receiver sheet.

The rotatable pressure roller 18 is mounted on the leading edge 24.
Opening 20 in the guide wall 16 for engaging one of the opposing edges of the receiver sheet 22 having a
Extends through. As will be described in greater detail below, the pressure roller 18 can move in a direction that engages the receiver sheet 22 to position the receiver sheet for printing or to eject the receiver sheet after printing. Can be released from the receiver sheet during the printing pass. In order to minimize the friction on the printing surface of the receiver sheet 22, a Teflon
A resilient pad made of a smooth surface material, such as tape or a strip of plush velvet, can be placed on the guide wall 14 under the pressure roller 18. In the state engaged with the receiver sheet 22,
As the pressure roller rotates, the receiver sheet is advanced clockwise along path 22 as shown.

Outside the passage 12, upstream of a conventional thermal printhead 30, a conventional die donor web roller 28 is supported for rotation in a counterclockwise direction. The dye donor web 31 runs under the print head 30,
It extends from a roll 28 to a dye donor take-up roller 32 located downstream of the printhead. Below the printhead, a rotatable platen roller 34
It extends through an opening 35 in the guide wall 16. Preferably, platen 34 comprises a rigid central shaft and an elastic outer layer. Depending on the duration of the printing cycle, the platen 34 engages either the die donor web 31 or the receiver sheet 22. The donor web and receiver sheet can be easily moved through the nip between printhead 30 and platen 34 without slipping the receiver sheet on the platen or adhering the receiver sheet to the printhead. , The coefficient of friction between the platen and the receiver sheet must be greater than the coefficient of friction between the donor web and the printhead. Also, the coefficient of friction between the receiver sheet and the donor web must be greater than the coefficient of friction between the donor web and the printhead.

The leading edge sensor lever 36 is connected to the pivot 3
8 has a contact end 37 that can be mounted on and extend into the passageway 12 to contact the leading edge 24.
At the opposite end of the lever 36 is a circumferentially extending sensor flag 4 which cooperates with a conventional optical sensor 42 of the type comprising a paired light source and detector.
0 is set. Upstream of the print head 30,
An optical sensor 46 substantially similar to the sensor 42
One is set up to sense the transition from the last cyan die of the color group before the die patch on 1 to the first yellow die patch of the current color group. One skilled in the art will recognize that the light source for sensor 46 is a cyan die
It must be red that can be shielded from light by patches, while the light sources for sensors 42 and 44
It will be appreciated that any cheap light source can be used.

According to the present invention, FIGS.
The printer device of FIG. 30 operates under the conventional programmable controller (not shown) in the following manner. First, when you turn on the printer,
The pressure roller 18 rotates counterclockwise, and if a receiver sheet is present, the receiver sheet is
-Discharge through an insertion / discharge port in the guide wall 14 upstream of the sensor 44, not shown in FIG. afterwards,
The head 30 moves onto the platen 34 and the pressure roller 1
8 moves on the guide wall 14. Sensor 44 detects when a new receiver sheet is inserted into passage 12 through the insertion / ejection port. Thereafter, the print head 30 is preheated. To set the dye donor web 31 in the correct position, the print head 3
0 indicates that the dye donor web has the print head and platen 3
4 until it is press-fit into the nip. The pressure roller 18 is at the raised position. The output from the sensor 46 is
Indicates whether a cyan die patch of the previous color group is present at the sensor. If a cyan patch is present, the platen 34
Rotate clockwise to advance the dye donor web until the patch has passed the sensor, indicating the transition of the current group of die patches. Thereafter, the platen is rotated a further predetermined distance to place the leading edge of the yellow patch of the current color group just past the nip between the printhead and the platen in place.

Thereafter, the print head moves upward from the platen and comes to the position shown in FIG. The pressure roller is
It descends and contacts the receiver sheet and rotates clockwise until the sensor 44 senses the passage of the trailing edge 26. In this case, the leading edge 24 has moved to the position of FIG. Then, the pressure roller rises and separates from the receiver sheet,
Movement in passage 12 stops. The printhead then descends and crimps the die donor web and receiver sheet at the nip between the printhead and platen, as shown in FIG. Thereafter, the platen is moved from the leading edge 24 to the contact end 3 of the sensor lever 36, as shown in FIG.
7 until the sensor flag 40 clears the sensor 42, and then rotates the sensor lever clockwise until the first color patch of the current color group of the dye donor web. This indicates that the receiver sheet is located at a position where printing can be started. Of course, printing can also be started when the platen rotates a predetermined length after passing the position where the sensor 42 is cleared. The location where sensor 42 is cleared is aligned with the printhead for each print pass, and a precise reference point from which the printer can return during subsequent print passes to correctly re-install the receiver sheet It is. Until the receiver sheet is completely passed, the friction between the contact end 37 and the back side of the receiver sheet prevents the sensor lever 36 from rotating in the reverse direction towards its initial position.

Thereafter, the platen rotates and the first print pass begins. As the platen continues to rotate, the platen slips the receiver sheet over the contact end 37 while the yellow patch is being printed, as shown in FIG. When the first print pass is completed, the trailing edge 26 is pushed out of the nip between the printhead and the platen,
Only the die donor web 31 remains sandwiched in the nip. The sensor lever 36 is released, rotates back to the position of FIG. 1, and the sensor 42 is shielded again. The platen 34 is then rotated a predetermined length until the first portion of the magenta patch is just past the nip between the printhead and the platen, as shown in FIG. The predetermined length can be easily determined because the size of the color patch on the dye donor web is known. Thereafter, the cycle described in this section and the previous section is repeated until printing with magenta and cyan patches on the dye donor web is completed to form a complete color image. When the last print pass is completed, the pressure roller 18 engages the receiver sheet and rotates counterclockwise to eject the print from the device.

[0034]

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become apparent from the following more detailed description of the preferred embodiment of the invention, as illustrated in the accompanying drawings. 7 to 30, those skilled in the art will appreciate the structure and operation of an actual embodiment of the present invention. The thermal printer device 10 can be housed in a housing consisting of a base 60 and a removable cover 62. An access door 64 is provided to close the opening of the cover 62 during printing. Usually, the door 64
Opened only when changing dye donor webs. The door 64 is mounted on a tie bar 70 that passes between a pair of support flanges 72, 74 extending upward from the two mechanism support plates, between the right mechanism support plate 66 and the left mechanism support plate 68. Installed by pivot.
Pivot flanges 73, 75 extend downwardly from the access door and are pivoted by bars 70,75.
Are engaged with the opposite end portions of the

As best shown in FIGS. 7, 9 and 17, the thermal printhead 30 has a mounting panel 78 below which the printhead is mounted.
It is supported by a sheet metal bracket 76. As described below, a pair of end flanges 80, 8
2 extends downward from the opposite end of the mounting panel,
To engage the opposite end of the platen's central shaft,
It has open round end slots 81,83. An integrally formed connection panel 84 extends upwardly and rearwardly from the mounting panel 78 and connects to the integral hinge panel 86. Hinge flanges 88, 90 are formed at opposite ends of the hinge panel 86 and extend downwardly and open round, loosely engaging the tie bars 70 inside the flanges 72, 74, respectively. End slots 92, 94 are provided. Interposed between the flanges 88, 90 is a hinge flange 89 extending downwardly with an open round end slot 93 securely engaging the tie bar 70, intermediate the flanges 88, 90. ing. Due to the arrangement of the hinge flanges, the printhead assembly can rotate around the tie bar 70 when the printhead moves and engages with the platen. You can also exercise. A set of ports 96, 98
Are formed in the connection panel 94 for passing electric wiring (not shown).

At the center of the mounting panel 78, a through opening 10
2 and a bracket 100 extending upward is formed. As shown in FIG. 17, a small coil spring 103 extends between the bracket 100 and the anchor (not shown) on the underside of the access door 64. Thus, when the access door is lifted, the printhead also rises to the position of FIG. However, if you move the printhead down toward the platen,
Only moderate tension spring force is applied to the access door. The elongated beam spring 104
It extends through the opening 102. Print head
In order to adjust the head load characteristic of the assembly, the bracket 100 can be adjusted up and down, but such a modification is also included in the scope of the present invention. As shown in FIG. 7, the beam spring 104
It preferably has a round cross section. However, the cross section of the beam spring may be of other shapes, and a beam spring having such a cross section is also included in the scope of the present invention. The beam spring 104 has at its opposing end a cam follower tip 106, 108 that extends laterally beyond the mounting panel 78 so that it can engage an actuation cam, described below. Prepare. A pair of stop hooks 110, 112 are formed at opposite ends of the mounting panel, and the cam follower tips 106,
It engages the beam spring inside 108 and applies a light preload of the beam spring to the bracket 100. As a result, the bracket approaches the platen,
The beam spring is held in the correct position with respect to the bracket 76 even if it moves away. By preloading the beam springs, the magnitude of the bending due to the disc cam, which will be described later, is also reduced. Therefore, when the beam spring bends, the bracket 100 acts as a fulcrum member. As shown in FIGS. 8, 9, 11, 13, and 29, an elongated finned heat sink 114 is provided on the top surface of the mounting panel 78 to absorb and dissipate excess heat from the printhead 30. It is installed in. Preferably, the fins of the heat sink extend parallel to the platen to reinforce the strength. The heat sink slot 116 has space to accommodate the beam spring. A set of air circulation fans 118, 120 are provided to help remove heat.

As best shown in FIGS. 16 and 17, the platen 34 has a rigid central shaft 1 inside.
22 has a central cylindrical portion formed by an elastic outer sleeve 34 'through which it passes. Support plate 66, 6
Eight bearing support flanges 124, 126 secure the platen so that it can rotate during printing. As the printhead lowers and forms a nip with the platen, the rounded end slots 81, 83 slip over the opposite end of the shaft 122 inside the bearing support flange. Preferably, a circumferentially extending groove (not shown) is formed to engage one of the end slots 81, 83 and allow the printhead assembly to be easily moved in the axial direction. Is preferred. Support flange 12
4, 126, a set of disk cams 132, 1
34 is mounted for free rotation on the opposite end of the shaft 122. As best shown in FIGS. 17 and 18, each disk cam has an essentially helical slot 136 into which the cam follower tips 106, 108 respectively extend. ing.
Each slot 136 has an opening 138 starting from the furthest from the center of the shaft 122 and towards the periphery of its respective cam. From the opening 138, the radius of the slot 136 from the center of the shaft 122 decreases,
Eventually, it will be the shortest at one end 140 of the slot.
Therefore, as the printhead assembly of FIG. 17 descends toward the platen, the tip 10 of the cam follower
6, 108 enter slot 136 through opening 138. Then, as described in more detail below,
As the cams 132, 134 rotate, the tips of the cam followers engage the walls of the slots 136 to move the printhead toward the platen. One skilled in the art will appreciate that a set of translation cams having curved slots for the tips 106, 108 may be used to move the printhead assembly, rather than a rotatable disk cam. right. When the printhead is fully engaged with the platen, the die donor web 31 extends between the guide rollers 1, extending between mechanism support plates 66, 68 located on the platen immediately in front of the platen.
41 is partially wrapped. The roller 141 is shown in FIGS.
This is shown in FIGS. 9, 13, 26, 29 and 30. By wrapping the die donor web on rollers 141, the die donor web is prevented from moving forward with the receiver sheet and is securely fed in the direction of the take-up roll 32.

As best shown in FIGS. 8, 9 and 11, the disc cams 132, 134 are rotated by the drive train. A motor 142 is mounted on the outer surface of the right support plate 66. Worm Gear 1
44 is the plate 6 on the output shaft of the motor 142
6 is installed at a position where the driven gear 146 is rotatably supported by the driven gear 146. Another driven gear 148 is the gear 1 as shown by the dotted line in FIGS.
It is installed coaxially so that it can rotate together with 46.
The gears 146 and 148 move from the plate 66 to the plate 68.
It is fixed on a shaft 150 that extends towards. See also FIG. As shown in FIG. 10, on the outer diameter of the disc cams 132, 134, a gear 1 is mounted on the opposite end of the shaft 150.
Gear portions 152, 154 that engage with 48 and 156 are provided. Therefore, the motor 142 can rotate in either direction and the disc cam 132, 1
Rotate 34 to move the print head closer to and farther from the platen.

FIGS. 18 to 25 show a method of positioning the print head by rotating the disk cam. FIG.
8 and FIG. 19, the tip 1 of the cam follower
06, 108 pass through openings 138 and slots 136
Has just entered, and there is sufficient space between the print head and the platen. About 90 disc cams
Turning to the position of FIGS. 20 and 21, the tip of the cam follower moves radially inward of the slot 136 and the printhead descends to just above the platen. While rotating 90 degrees to the position of FIGS. 22 and 23, the tip of the cam follower continues to move inward in slot 136 and the printhead contacts the platen to feed the die donor web and receiver sheet. To form a nip. During a further 90 degree rotation to the position of FIGS. 24 and 25, the beam spring 104 curves and presses the printhead against the die donor web;
When the die donor web is crimped to the receiver sheet and the receiver sheet is crimped to the platen, the tips of the cam followers engage the radially outer sides of the slots 136. Those skilled in the art will appreciate that by appropriately selecting the bending strength of the beam spring, (a) when the printhead is activated, the die is transferred to the receiver sheet by heat,
(B) It will be appreciated that when the platen rotates, sufficient engagement force can be obtained to move the die donor web alone, or both the die donor web and the receiver sheet.

FIGS. 8, 9, 13, 17, and 26
As shown in the figure, the disk cam 13 on the right side of the printer
2 has on its periphery a radially extending ear 158 covering an arc of about 90 degrees, starting from the opening 138 and proceeding along the peripheral opposing slot 136. See also FIGS. 18, 20, 22, and 24. The cam follower 160 is supported by a slide 162 mounted on the outer surface of the right mechanism support plate 66. The cam follower 160 has at its lower end a shaft engaging shoe 16 in line contact with the upper part of an elongated shaft 166 on which the pressure roller 18 is fixed.
4 is provided. As best shown in FIG. 26, the opposite end of the shaft 166 is rotatably supported by bearing pockets 168 formed in the inner surface of the left mechanism support plate 68. To adjust the angle of the pressure roller, another bearing pocket (not shown) can be formed. Cam Follower 160
It is held around the disk cam 132 by a set of elastic drive belts 172, described briefly below. Therefore, when the disc cam 132 rotates, the lug 1
58 engages and disengages with the cam follower 160, and as a result, the pressure roller 18 engages and disengages with the receiver sheet. At the same time, as already explained, the print head 3
4 is a spiral groove 136 and cam followers 106, 108
And engages and disengages with the platen.

As shown in FIG. 16, a part of the passage 12
From the mechanism support plates 66 and 68 to each other,
It is formed between a part of the guide walls 14 and 16 extending inward. During printing, the receiver sheet 22 must be held perpendicular to the printhead 30 as the receiver sheet is being advanced by the platen 34. In the case of the present invention, in order to maintain the receiver sheet perpendicular to the print head, the rotation axis of the pressure roller 18 is inclined at a slightly acute angle in the direction of movement of the receiver sheet through the passage 12. As a result, when the pressure roller rotates, the right edge of the receiver sheet is
It is driven by a flat, vertical guide surface 167 formed on a support plate 66 between its respective guide walls 12,14. For example, the shaft 166 is connected to the platen 34.
About 10 degrees from a direction parallel to the rotation axis. Therefore, when the pressure roller 18 rotates in contact with the receiver sheet, the right edge of the receiver sheet is forcibly engaged with the guide surface 167.

The figure shows that the receiver sheet can be repeatedly positioned relative to the guide surface 167 along most of the length between the pressure roller and the printhead or passageway 12 at the printhead. Although the rollers 18 are shown, sometimes a slight deviation from the guide surface 167 is observed as the leading edge 24 approaches the printhead. The cause is believed to be due to the inherent stiffness of the receiver sheet as it approaches the printhead. A small leaf spring 165 is provided as shown in FIGS. 13, 14 and 26 to eliminate such misalignment that may cause misalignment between subsequent print passes. The leaf spring 165 is mounted on the inner surface of the left mechanism support plate 68 slightly upstream of the platen. At this point, the spring engages the left edge of the misaligned receiver sheet 22 and pushes the receiver sheet back against the guide surface 167 on the opposite side of the printer.

Referring to FIGS. 27 and 28,
The disc cam 132 has an axially extending sensor actuation flange 169, a portion of which is shown in FIGS.
Is provided. Flange 169 overlies the ear by approximately 25 degrees and extends circumferentially at an angle of approximately 210 degrees. On the outer surface of the right mechanism support plate 66 are sensors 42 and 4 which cooperate with an actuation flange 169.
Four similar limit switches 171 are provided that engage the ears 158 and the optical sensor 173. FIG. 27 shows the disc cam 132 when the printhead 30 is fully engaged with the platen 34 and the tip 106 of the cam follower is near the end 140 of the spiral slot 136. In this state, the switch 17
1 is turned off, becomes a state of logic "1", and the sensor 17
3 is shielded from light by the flange 169 and is in a state of logic "1". When the disk cam rotates counterclockwise to move the printhead upward, after about 15 degrees of rotation, the sensor 173 is released from the light-shielded state and has a logic "0".
And printing stops at this point. Further, it rotates about 180 degrees, and the ear 158 near the opening 138.
Enters the spiral slot 136, the switch 171 is turned on and is in a logic "0" state. At this point, the printhead has moved upwards away from the platen, leaving sufficient space between them. Further, when rotated about 30 degrees, the sensor 173 is again shielded from light by the flange 169, and becomes a state of logic "1". Turning another 60 degrees, switch 71 is turned off, away from ear 158, and is in a logic "1" state, indicating that access door 64 is open. Turning approximately five more degrees, the cam follower tip 106 comes to the opening 138. Outputs from the switch 171 and the sensor 173 are sent to a conventional controller of the present apparatus described later. The relative position of switch 171 and sensor 173 can be used to detect the position of the device at any particular time during the cycle.

The pressure roller 18 and the platen 34 share a common drive train. The pulley 170 having the double groove is provided on the shaft 166 outside the engagement shoe 164.
Is fixed on the right end. A set of O-ring belts 172 extend upward from pulley 170 to similar pulleys 174 and are secured on the right end of central shaft 122 outside of disc cam 132. Belt 17
2 engages pulleys 170, 172, thereby creating a tension that engages cam follower 160 around disk cam 132. Of course, pulleys with a single groove and one belt could also be used. The spring 176 shown in FIGS. 8, 9 and 16 is fixed to the pulley 174 and engages a radially extending surface 178 on the disc cam 132, thereby affecting alignment with the printhead. An axial load is placed on the shaft of the platen to the right of the printer to prevent applied axial movement of the platen. 8, 9, and 26
30 and on the left side of the printer, the pulse motor 1 on the left mechanism support plate 68.
80 are installed. The output shaft of the motor 180 extends outside the support plate 68 and is fitted with an output pinion gear 182. 10 to 13, FIG.
5, the drive train extends from the pinion 182 to the platen 34, as best shown in FIGS. The drive train includes a driven gear 184 engaged with a pinion 182 and a gear 18 fixed on a central shaft 122 outside the disc cam 134.
8 with a coaxial gear 186 engaged with the same. As shown in FIG. 16, a gear 190 is mounted between the gear 188 and the disc cam 134 so as to be rotatable about the shaft 122. A clutch spring 192 is secured to the central shaft 122 and frictionally engages the gear 190 with the internal side surface of the gear 188. As shown in FIGS. 10 and 30, the gear 190 is
8 is engaged with a gear 194 that is rotatably supported on a shaft extending outwardly from the shaft 8. The gear 194 is engaged with a gear 196 fixed to the die donor winding roll 32. Preferably, gear 196 includes platen 34
Preferably, it is driven at a slightly faster speed. As a result, a weak tension is maintained in the die donor web during use. The clutch spring 192 can slip so as not to apply too much tension. Finally, FIG.
As shown in FIG. 1, the pawl 198 for preventing reverse rotation is
It is pivotally mounted at a position which engages the outer gear 194 to prevent reverse rotation of the take-up roll 32 when the receiver sheet is ejected from the printer.

During operation of the printer, a die receiver is inserted into passage 12 through an elongated opening 200 provided in housing cover 62. A plurality of ribs 206 are formed on the top surface of the base 60 to support and guide the sheet as it moves through the passageway 12 as the pressure roller 18 rotates. FIG.
As shown schematically, housing cover 62 includes a set of insertion / ejection guides 20 within opening 200 to assist in introducing and withdrawing the receiver sheet into the passageway.
8, 208 'can be supported. Schematic power supply 210 and conventional programmable controller 21
2 is mounted on the base 60 and is operatively connected to various motors, sensors, printheads and other components described above. An on / off switch 214 is provided on the front of the printer, along with a set of lamps 216 for indicating operating conditions.

From the above description, those skilled in the thermal printer art will appreciate that the motor 142 drives the disk cams 132, 134 to move the lower printhead 34 up. When the cam rotates to move the lower print head upward, the lug 158 engages the cam follower 160 to move the pressure roller 18 up and down to engage the receiver sheet 22 or the like. , Or withdrawal. At the same time, the switch 171 and the sensor 173
The controller 212 is notified of when the receiver sheet can be loaded, when printing should be started and stopped, when the platen can be moved up sufficiently to advance the receiver sheet, and when the access door opens. Motor 180 drives platen 34 to advance the dye donor web and receiver during printing and advance the dye donor web during recirculation of the receiver sheet. While the printed material is being ejected from the apparatus, the direction of rotation of motor 180 is reversed and motor 142 rotates the disc cam to lower the pressure roller.

[0047]

The present invention provides various advantages. Printhead assemblies are simpler and less expensive than conventional ones. The use of beam springs ensures that the engagement between the printhead and the platen is essentially uniform over the entire width of the platen. In the preferred embodiment, since only one fulcrum is used, an essentially uniform engagement can be achieved more easily as compared to the prior art. Because the cam is slotted, the printhead can transition essentially from a loaded state to an unloaded state in an essentially smooth manner. The plate cam is used only during positioning to print the printhead, but so that the operator can fully open the door to change the donor web.
Open the access door slightly upwards.

The present invention has other advantages. The entire printer is simpler and less expensive than conventional printers.
The use of a closed loop passage for recirculating the receiver sheet allows it to be installed close to the position required to print the leading edge of the receiver sheet, thereby providing a dedicated securing mechanism for the receiver sheet It can operate with approximately the same print cycle time as a printer using a large print drum. It does not require a large print drum, so a small diameter platen can be used, which allows it to be used with large print drums that typically require a custom printhead due to the large diameter Inexpensive commercially available printheads can be used. The receiver sheet can be repositioned correctly for each print pass.

The present invention has other advantages. While the prior art required a dedicated drive system for winding the used donor web, the present invention does not. Since the movement of the donor web can be controlled by driving the platen, only one sensor is needed to detect the first part of the color group, and then the individual rotation is achieved by simply rotating the platen a predetermined length. Color patches can be accurately located.
By simply operating the sensor lever, the leading edge of the receiver sheet can be accurately positioned and ensure correct alignment during subsequent printing passes.

<Other features of the present invention> Claims 1 to 7
In addition to the features described above, the present invention can include the following features. a. Roller means extending in the passage for recirculating means for feeding the receiver sheet through the closed loop passage in the printing direction, and the leading edge of the receiver sheet passes between the platen and the dye donor web. 2. The method according to claim 1, further comprising: means for sensing and generating a signal in response to the signal, and in response to the signal, means for releasing the roller means from the receiver sheet before printing begins. Thermal printer. b. The means for rotating the platen also rotates the roller means, the roller means being supported on a shaft, and the means for disengaging the roller means comprises a cam and a cam follower engaged with said cam and shaft. And a means for moving the cam to move the cam follower and shaft, thereby engaging and disengaging the roller means with the receiver sheet. c. Means for rotating the platen, a first pulley capable of rotating with the platen, a second pulley mounted for rotation with the shaft and roller means, and a roller for rotation. A thermal printer according to feature b, comprising an elastic drive belt engaged with the first and second pulleys for transmitting to the means and maintaining engagement between the cam and the cam follower. d. Wherein the platen includes a central shaft having an end, and the cam includes a plate cam mounted for rotation about the end, wherein the means for moving the cam rotates the cam. C The thermal printer according to 1. e. Wherein the platen includes a central shaft having an end, and the cam includes a plate cam mounted for rotation about the end, wherein the means for moving the cam rotates the cam.b The thermal printer according to 1. f. To complete the printing of the receiver sheet,
Steps (d)-(j) for subsequent colors of the group
3. The method according to claim 2, further comprising the step (k) of repeatedly performing
The method described in. g. 4. The thermal printer of claim 3 wherein said means for engaging also moves the beam spring and printhead to engage the printhead with the die donor web before bending the beam spring. h. 4. The thermal printer of claim 3 wherein the means for engaging also moves the beam spring and the printhead to disengage the printhead from the die donor web before bending the beam spring. i. The means for engaging includes a set of movable cams and means for moving the cams to force the printhead into engagement with the die donor web, each cam comprising:
4. The thermal printer according to claim 3, wherein each slot has a radially shorter distance from the axis of rotation of the platen, and each slot engages one of the opposing ends. j. The thermal printer of feature i, wherein each slot is open toward the periphery of each cam so that the printhead, fulcrum member, and beam spring can disengage from the cam. k. The thermal printer of claim j, wherein said means for supporting the printhead to facilitate engagement and disengagement with the dye donor web is pivotally mounted to a frame of the printer. l. A housing housing the printer, the housing having an access door and support means connected to the access door, wherein the support means rotates about the pivot and moves the access door upward. The thermal printer according to k. m. The thermal printer of claim 1, wherein the access door and the support means are connected by a spring. n. The thermal printer according to Feature i, wherein the cam is rotatable. o. The thermal printer of Feature n, wherein each plate cam is mounted for rotation about one end of a platen shaft. p. 5. The printhead assembly of claim 4, wherein the support means comprises means for pivotally mounting the printhead to a printer frame such that the printhead can be easily engaged and disengaged from the die donor web. q. Further comprising a set of hooks extending from the support means;
5. The printhead assembly of claim 4, wherein one hook engages each opposing end of the beam spring to bias the spring into contact with the fulcrum member. r. 5. The printhead assembly of claim 4, further comprising a set of end flanges extending from said support means, each end flange configured to engage one of the opposite shaft ends of a platen. . s. After passing between the platen and printhead,
6. The thermal printer of claim 5, further comprising a take-up roll located downstream of the printhead for receiving the dye donor web and rotated by rotating means. t. Rotating means for rotating the winding drive member together with the platen driving member fixed on the platen shaft, the winding driving member rotatably mounted on the platen shaft, and the platen shaft; The thermal printer of feature s, comprising: a slip clutch member; and means for transmitting rotation of the take-up drive member to the take-up roll. u. The die donor web includes a continuous color group of patches of different die, means for sensing the transition from the previous color group to the current color group and generating a signal, and the transition portion is downstream of the printhead. Means for rotating the platen in accordance with the signal until the predetermined position of the thermal printer is reached. v. (J) following the first color transition, continuously rotating the platen in the printing direction to advance the receiver sheet between the platen and the dye donor web;
(K) advance the dye donor web by a predetermined distance, thereby positioning the first portion of the next color of the current color group downstream of the printhead, and then stopping platen rotation; Continuously rotating the print head from the die donor web; (m)
Re-introducing the receiver sheet between the dye donor web and the platen; (n) re-engaging the printhead with the dye donor web; and (o) advancing both the dye donor web and the receiver sheet. Re-rotating the platen in the printing direction, and (p) actuating the print head simultaneously with step (n) to transfer the next color die of the current color group to the receiver sheet. The method of claim 6, further comprising: w. (Q) To complete printing on the receiver sheet,
The method of claim v, further comprising repeating steps (j) through (p) for subsequent colors of the current color group. x. A sensor lever supported by a pivot having a free end located downstream of the printhead such that the sensing and signal generating means engages the leading edge;
8. The thermal printer according to claim 7, further comprising means for detecting movement of a sensor lever when contact between the free end and the leading edge moves. y. The thermal printer of Feature x, wherein the sensor lever is sufficiently rotatable about a pivot such that the leading edge can be advanced into the path in the printing direction. z. A receiver, from and toward the platen, adapted to rotate in the printing direction with at least a portion of the passage being in the passage for engagement with a receiver sheet or die donor web. A closed loop path for recirculating the sheet in the printing direction, wherein said moving means is adapted to continuously transfer different dies from the die donor web to the platen through the closed loop path in the printing direction and vice versa. The thermal printer of feature x, wherein the receiver sheet is recirculated toward the platen.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of the thermal printer of the present invention at successive stages of a printing cycle.

FIG. 2 is a schematic diagram of the thermal printer of the present invention at each successive stage of the printing cycle.

FIG. 3 is a schematic diagram of the thermal printer of the present invention at each successive stage of the printing cycle.

FIG. 4 is a schematic diagram of the thermal printer of the present invention at successive stages of a printing cycle.

FIG. 5 is a schematic diagram of the thermal printer of the present invention at each successive stage of the printing cycle.

FIG. 6 is a schematic diagram of the thermal printer of the present invention at each successive stage of the printing cycle.

FIG. 7: Access door and thermal printhead
FIG. 3 is a front and right side perspective view of the actual embodiment of the thermal printer of the present invention, with the pivot moving upward about the center.

8 is a perspective view of the printer of FIG. 7 with the printhead in a lowered position, with the upper housing cover, the printhead sheet metal support, and a set of drive belts removed for illustrative purposes.

FIG. 9 illustrates the printer of FIG. 7 with the upper housing cover and a set of drive belts removed and the printhead and its sheet metal support moved upward about a pivot for convenience of explanation. It is a perspective view.

FIG. 10 is a perspective view of the back and left sides of the printer of FIG. 8, as viewed from opposite corners.

FIG. 11 is a partial view of the gear train including the anti-reverse pawl engaging a gear of the gear train shown in FIG. 10;

FIG. 12 is a front view of the printer of FIG.

FIG. 13 is a plan view of the printer of FIG.

FIG. 14 shows a biasing spring for pressing the receiver sheet against opposing sides of the printer, FIG.
FIG. 3 is a partial view taken along line BB of FIG. 3.

FIG. 15 is a rear view of the printer of FIG. 8;

FIG. 16 is a schematic cross-sectional view taken along line 16-16 of FIG.

FIG. 17 is an exploded perspective view showing a part of the front and right sides of the printhead assembly of the present invention.

FIG. 18 is a schematic illustration of the position of the platen, printhead assembly, and helical cam with the printhead completely moved upward from the platen.

FIG. 19 is a schematic diagram of the position of the platen, printhead assembly and helical cam with the printhead completely moved upward from the platen.

FIG. 20 is a schematic diagram of the position of the platen, printhead assembly and spiral cam with the printhead lowered onto the platen.

FIG. 21 is a schematic diagram of the position of the platen, printhead assembly, and spiral cam with the printhead lowered onto the platen.

FIG. 22 illustrates the platen with the printhead lowered and engaged with the platen, pressing the die donor web alone or both the die donor web and the receiver sheet into the nip between the print head and the platen; 5 is a schematic diagram of the position of the printhead assembly and the helical cam.

FIG. 23 illustrates the platen, with the printhead lowered and engaged with the platen, pressing the die donor web alone or both the dye donor web and the receiver sheet into the nip between the print head and the platen. 5 is a schematic diagram of the position of the printhead assembly and the helical cam.

FIG. 24 with the beam spring curved by a helical cam to print on the receiver sheet and to provide the necessary pressure to feed the die donor web and / or the receiver sheet. , Platen, printhead assembly and spiral cam location.

FIG. 25 with the beam spring curved by a helical cam to print on the receiver sheet and to supply the necessary pressure to feed the die donor web and / or the receiver sheet. , Platen, printhead assembly and spiral cam location.

FIG. 26 is a perspective view of the right side and the back side of the printer with the right mechanism support plate removed for the sake of simplicity.

FIG. 27 is a view taken along line 27-27 of FIG. 13 with the right mechanism support plate removed for simplicity.

FIG. 28 is a timing chart of an optical sensor and a limit switch that are activated when the disk cam of FIG. 7 rotates.

FIG. 29 is a view taken along line 29-29 of FIG. 13 with the left mechanism support plate removed for simplicity.

FIG. 30 is a schematic perspective view of the right side and the back side of the printer of FIG. 8 with the left mechanism support plate and the left helical cam removed for simplicity.

[Explanation of symbols]

10. . . Thermal printer device 12. . . 13. Closed loop passage for receiver sheet . . External guide wall 16. . . Internal guide wall 18. . . Crimping roller 20. . . Internal guide wall (1) for pressure roller (18)
6) Opening . . Receiver sheet or sheet 24. . . Front edge 26. . . Trailing edge 28. . . Dye donor web supply roll 30. . . Thermal print head 31. . . Daidner's web . . Dye donor web take-up roll 34. . . Platen roller 34 '. . . Elastic outer sleeve on platen roller (34) 35. . . 36. Opening of internal guide wall (16) for platen roller (34) . . Leading edge sensor lever 37. . . 38. Contact end of leading edge sensor lever (36) . . Pivot for leading edge sensor lever (36) 40. . . Sensor on the leading edge sensor lever (36)
Flag 42. . . Optical sensor for sensor flag (40) 44. . . Trailing edge sensor for trailing edge (26) 46. . . Sensor for leading edge of next die triplet . . Housing base 62. . . Removable housing cover 64. . . Access door 66. . . Right mechanism support plate 68. . . Left mechanism support plate 70. . . Tie bar 72,74. . . Flanges 73, 75 on right and left mechanism support plates (66, 68). . . 76. Flange extending downward on access door (64) . . Seat metal mounting bracket 78. . . Printhead mounting panel 80, 82. . . Downward end flange 81,83. . . Open round end slot in downward end flange (80, 82) 84. . . Integrated upward connection panel 86. . . Hinge panel 88, 90. . . Downward hinge flange 92,94. . . 70, 98, 98 with open, rounded end slots for engaging with . . Electric cable port 100. . . Center bracket 102. . . Opening of central bracket (100) 103. . . Coil spring between central bracket (100) and access door (64) 104. . . Elongate beam springs 106,108. . . Tip of cam follower 110,112. . . Locking hook 114. . . Heat sink with fins 116. . . Slots for beam springs (104) 118,120. . . Air circulation fan 122. . . Central shafts 124, 126 of platen rollers (34); . . Bearing support flange 128,130. . . . 132, 134. . . Rotatable disk cam on central shaft (122) 136. . . Helical slot in disc cam (132, 134) 138. . . Opening over the entire radius 140. . . 141. Shortest radius end of helical slot (136) . . Guide roller for die donor web (31) 142. . . Motor 144. . . Worm gear 146. . . Driven gear 148. . . Driven gear coaxial with driven gear (146) 150. . . Shafts for driven gears (146, 148) 152, 154. . . Gear on disk cam (132) 156. . . Gear on left end of driven gear shaft (150) 158. . . Ear-like members extending in the radial direction 160. . . Come Follower 162. . . Slide 164. . . Engaging shoe 165. . . Leaf for engaging with seat (22)
Spring 166. . . Shaft for pressure roller (18) 167. . . Flat, vertical guide surface 168. . . Bearing pocket 169. . . Sensor operating flange 170. . . Pulley 171. . . Limit switch 172. . . O-ring drive belt 173. . . Optical sensor 174. . . Pulley 176. . . Spring arm 178. . . Radially extending surface 180. . . Pulse motor 182. . . Output pinion 184. . . Driven gear 186. . . 188. Gear coaxial with driven gear (184). . . Fixed coaxial gear 190. . . Rotatable gear 192. . . Clutch spring 194. . . Gear 196. . . Gear 198. . . Reverse rotation prevention nail 206. . . Ribs 208, 208 '. . . Insertion / discharge guide 210. . . Power supply 212. . . Control panel 214. . . On / off switch 216. . . Status indicator lamp

 ──────────────────────────────────────────────────続 き Continued on the front page (31) Priority claim number 641,323 (32) Priority date April 30, 1996 (33) Priority claiming country United States (US) United States of America New York 14624 Rochester Lexington Parkway 20

Claims (7)

[Claims] 1. A thermal printer for printing on a receiver sheet having a leading edge and a trailing edge, comprising: an elongated rotatable platen; an elongated printhead mounted parallel to the platen; Directing the receiver sheet in a printing direction from and back to a platen adapted to rotate in the printing direction, with at least a portion thereof being in the passage for engagement with the sheet or die donor web. A closed loop path for recirculation, a supply roll of die donor web located upstream of the printhead, engaging the printhead with the die donor web, engaging the die donor web with the receiver sheet, To engage the receiver sheet with the platen, (a) pre-heat to transfer the die to the receiver sheet (B) sufficient pressure is applied when the platen rotates in the printing direction to move the die donor web or both the dye donor web and the die receiver sheet between the print head and the platen. Means for moving the printhead into a passage opposite that portion of the platen for hanging; and for moving the die donor web or both the die donor web and the die receiver sheet between the printhead and the platen. Means for rotating the platen in the printing direction; and means for recirculating the receiver sheet through a closed loop passage in the printing direction for continued thermal transfer of different dies from the die donor web. A thermal printer, characterized in that: 2. A method of thermally printing on a receiver sheet using a dye donor web consisting of a continuous color group of patches of different dies, comprising: (a) elongating a thermal print head with a die donor; Engaging one side of the web, engaging the other side of the die donor web with one side of the receiver sheet, and engaging the other side of the receiver sheet with a rotatable platen; (b) Rotating the platen in the printing direction to advance both the die donor web and the receiver sheet; and (c) transferring the first color die of the color group to the receiver sheet simultaneously with step (b). for,
Activating the printhead; and (d) continuing to rotate the platen in the printing direction after the transfer of the first color to advance the receiver sheet from between the platen and the dye donor web. (E) advance the dye donor web by a predetermined length, thereby continuing to rotate the platen in the print direction to position the beginning of the next color in the color group at a location downstream of the printhead. (F) detaching the printhead from the dye donor web; and (g) recirculating the receiver sheet in the printing direction, between the die donor web and the platen. Re-introducing the receiver sheet; and (h) re-engaging the printhead with the die donor web. (I) rotating the platen again in the printing direction to advance both the dye donor web and receiver sheet; and (j) simultaneously with step (i), the die of the next color in the color group. Actuating the printhead to transfer the image to the receiver sheet. 3. A rotatable platen having a set of opposing shaft ends, a printhead extending parallel to the platen, and the printhead under pressure causing the die donor web to contact a receiver sheet, the receiver comprising: Means for supporting a printhead adjacent to the platen so that the sheet can be brought into contact with the platen, comprising: an elongate beam spring having opposing ends; To engage the beam spring between
A fulcrum member extending from the support means; (a) when the printhead is rotated to thermally transfer the die to the receiver sheet; and (b) a die donor web or die between the printhead and the platen. To rotate both the donor web and the die receiver sheet, when the platen is rotated, the beam springs are bent and the printhead is engaged with the die donor web by applying sufficient force to transfer the die donor web to the receiver. Means for engaging a beam spring at opposite ends for engaging the sheet and engaging the receiver sheet with the platen. 4. A printhead assembly for a thermal printer of the type comprising a rotatable platen having a set of opposed shaft ends, the printhead assembly extending parallel to the platen; Means for supporting a printhead adjacent to the platen so that the die donor web can be pressed against the receiver sheet moving with the platen; an elongate beam spring having opposing ends; To engage the beam spring between the ends,
A fulcrum member extending from the support means, whereby the opposite end engages the thermal printer, causing the beam spring to bend, thereby thermally transferring the die to the receiver sheet when the printhead is activated. Print head assembly, wherein the print head can be pressed against the die donor web with sufficient force for the purpose. 5. A thermal printer for printing on a receiver sheet, comprising: an elongated rotatable platen; an elongated printhead mounted parallel to the platen; and a die located upstream of the printhead. A donor web supply roll and a printhead are engaged with the die donor web and, in the absence of a receiver sheet, so that the platen can withdraw the dye donor web from the supply roll.
Means for pressing the die donor web against the platen with sufficient force as the platen rotates, and the printhead moving the die donor web against the platen to move the die donor web between the printhead and the platen. Means for rotating the platen during press-fitting. 6. A method for thermally printing using a dye donor web consisting of a continuous color group of patches of different dies, comprising: (a) rotating one side of the dye donor web in an elongated roll. Engaging a possible platen and engaging the other side with an elongated thermal printhead; (b) rotating the platen in a printing direction to advance the die donor web; (c) the platen And upstream of the printhead, sensing the transition between the end of the previous color group and the previous portion of the current color group; and (d) after sensing, the dye donor web by a predetermined length. Forward, thereby positioning the first part of the current color group at a location downstream of the printhead.
(E) detaching the printhead from the dye donor web; and (f) disengaging the print head from the dye donor web; and
Introducing a receiver sheet; (g) engaging the printhead with the dye donor web;
Engaging the die donor web with the receiver sheet and engaging the receiver sheet with the platen; and (h) re-rotating the platen in the printing direction to forward both the die donor web and the receiver sheet. (I) activating the printhead to transfer the first color die of the current color group to the receiver sheet simultaneously with step (h). 7. A thermal printer for printing on a receiver sheet having a leading edge and a trailing edge, comprising: an elongated rotatable platen; an elongated printhead mounted parallel to the platen; For receiving a receiver sheet in a printing direction from a platen adapted to rotate in the printing direction, with at least a portion thereof being in the passage for engagement with the receiver sheet or die donor web. A passage, a supply roll of a dye donor web located upstream of the printhead, and applying pressure to engage the printhead with the dye donor web, engage the die donor web with the receiver sheet, and remove the receiver sheet. A hand for moving the printhead into a passage opposite that portion of the platen to engage the platen. Means for rotating the platen in the printing direction to move the dye donor web or both the dye donor web and the receiver sheet through between the printhead and the platen; and Means for sensing and generating a signal when it arrives at a predetermined location downstream of the head; anda printhead for transferring the die between the die donor web and the receiver sheet according to the other signal. And a means for moving a receiver sheet in a path for continuous thermal transfer of different dies from a die donor web.