JP2969390B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus in which a recording paper such as a business card sheet, a card, and a postcard is sandwiched between a head and a platen, and the head is heated according to image information to print the recording paper. .

[0002]

2. Description of the Related Art Generally, a recording paper and a thermal transfer ribbon are provided between a head and a platen disposed between the pair of conveying means and the front and rear in the conveying direction of the recording paper. 2. Description of the Related Art A technique is known in which printing is performed on recording paper by heating the head in accordance with image information by sandwiching the thermal paper.

In such an apparatus, the head and the platen are brought into pressure contact with the recording paper or the like during printing, and the head and the platen are separated from each other when the recording paper is carried in / out between the head and the platen. Need to be Conventionally, a head is provided so as to be able to press against and separate from a fixed platen.

[0004]

However, when the head is moved as in the above-mentioned conventional example, the head is backlashed due to the displacement mechanism for displacing the head, and when the head and the platen are brought into pressure contact with each other. It is difficult to accurately set the head at a fixed position.

Therefore, when the head is heated in accordance with the image information and printing is performed on the sheet, there is a possibility that a printing shift may occur. Therefore, if the head is fixed and the platen is separated from the recording paper, the above problem can be solved. However, in this case, the following problem may newly occur. That is, since the recording paper is transported in a state in which the recording paper is pressed against the head surface by the pair of transportation means in the transportation direction of the recording paper, heat that has heated the head during printing remains on the head. There is a disadvantage that unnecessary printing is performed on the recording paper conveyed by the heat of the head.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and is directed to an image forming apparatus which sandwiches a recording sheet between a head and a platen, heats the head according to image information, and prints on the recording sheet. By keeping the in a fixed position, the printing quality is improved by eliminating the printing misalignment,
An object of the present invention is to provide an image forming apparatus free from printing errors by surely keeping the recording paper separated from the head during non-printing.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a printing head, a platen which is at least displaced between a press contact position and a separation position where a recording paper is sandwiched between the printing head, A transport unit disposed upstream or downstream of the transport with respect to the platen for reciprocating the recording paper between the head and the platen, and pressing the transport unit against the head when printing the transport unit. The recording paper is displaced in the conveying direction in a direction in which the recording paper is pressed against the head, and during non-printing, the recording paper is separated from the head by following the separation of the platen from the head, and the conveyance direction is changed in the conveying direction. And a displacing means for displacing.

[0008]

When the recording paper is conveyed from the platen side to the conveyance means side, the platen is displaced to the pressure contact position and the conveyance means is displaced to perform printing, while the recording paper is conveyed from the conveyance means side to the platen side. Is displaced to the separated position and the transfer means is displaced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. <Configuration> First, the configuration of this device will be described. The overall configuration diagram 1, as an image forming apparatus, a large number of sheets continuously printing apparatus business cards is illustrated.

This device is arranged facing the operator with the right side of FIG. 1 facing the front. This device is connected to a personal computer (not shown) or the like and operated.

Reference numeral 1 denotes a casing of the apparatus.

On one side of the apparatus (in this example, on the upper right side of FIG. 1), a paper feeding means, for example, a paper feeding mechanism 2 for feeding business card printing sheets (recording paper) one by one is provided.

Further, a receiving layer is formed by a pre-treatment material such as a binder material as a pre-treatment by thermal transfer on a surface of a sheet sent from a first printing means, for example, the sheet feeding mechanism 2 away from one side of the apparatus. After that, a receiving layer / image forming mechanism 3 for printing characters, graphics, etc. on the receiving layer by thermal transfer is provided.

This receiving layer forming step is not necessary for coated paper which has been subjected to surface treatment in advance, but is necessary for plain paper, for example, in order to improve the adhesion of dyes.
Further, the thermal transfer system includes a fusion type in which the dye is adhered to the sheet in a molten state and a sublimation type in which the dye is adhered in a vaporized state. In the case of the sublimation type, the formation of the receptor layer is particularly necessary.

Further, on one side of the apparatus (in this example, on the lower right side of FIG. 1), the surface of the image-formed sheet conveyed from the receiving layer / image forming mechanism 3 is protected by thermal transfer with a transparent material or the like. A protective layer forming mechanism 4 for covering the layer is provided.

A sheet feeding path 5 for conveying a sheet from the sheet feeding mechanism 2 to the receiving layer / image forming mechanism 3 is provided. Further, a paper discharge path 6 for conveying a sheet from the receiving layer / image forming mechanism 3 to the protective layer forming mechanism 4 is provided.
Reference numeral 7 denotes a feed roller provided in the paper discharge path 6.

Downstream of the protective layer forming mechanism 4, there is provided a paper discharge tray 8 for storing printed sheets. Configuration of Paper Feeding Mechanism 2 The paper feeding mechanism 2 will be described with reference to FIGS.

Reference numeral 9 denotes a paper feed tray for stacking and storing sheets. On the side of the paper feed tray 9, an alignment guide 10 that moves in the width direction of the paper feed tray 9 and aligns the sheet bundle in its short direction is provided. At the leading end of the paper feed tray 9, there is provided a separation gate 11 for separating and sending only one sheet from the gap with the paper feed tray 9. The separation gate 11 can be moved up and down to adjust the gap with the paper feed tray 9 according to the thickness of the sheet. Below the sheet feed tray 9, there is provided a feed roller 12 that feeds out from the lowest sheet on the sheet feed tray 9.

Downstream of the paper feed tray 9, a pair of feed rollers 13 is provided. The feed rollers 13 are provided so as to be separated from each other and pressed against each other.

Downstream of the feed roller 13, there is provided a pair of registration rollers 14 for abutting the leading edge of the sheet to correct the skew of the leading edge of the sheet. A switching gate 15 for switching the transport path is provided downstream of the registration rollers 14. The switching gate 15 is always urged by a spring 16 so as to close the paper feed path 5 and open the paper discharge path 6.

The feed roller 12, the feed roller 13, the registration roller 14, and the like are connected to a second drive system described later.

The sheet sensor 17 counts the number of fed sheets and detects the trailing edge of the sheet. Structure of Receptive Layer / Image Forming Mechanism 3 Next, the receiving layer / image forming mechanism 3 will be described with reference to FIG. 1 and FIGS. Downstream of the switching gate 15, a pinch roller 19 is attached to a drivable grid roller 18.
Are slidably pressed. The grid roller 18
A large number of irregularities are formed on the outer periphery so that the sheet can be fed without slipping. The pinch roller 19
Moves on the outer periphery of the grid roller 18 following the operation of a platen described later (see FIGS. 2 and 3).

Downstream of the grid roller 18 and the pinch roller 19, there is provided a head 20 for heating according to image information during thermal transfer. The thermal transfer ribbon 21 and the sheet are superposed between the head 20 and a platen to be described later, and are thermally transferred in a state of being pressed against each other. Reference numeral 22 denotes a head cooling fan.

Feed reel 23 wound with thermal transfer ribbon 21
And the thermal transfer ribbon 2 drawn from the feed reel 23
And a take-up reel 24 that winds 1 through the head 20.

A transport roller 25 for transporting the thermal transfer ribbon 21 is provided. By using a torque limiter (not shown) for the transport roller 25 and the take-up reel 24, thermal transfer due to a change in the winding diameter of the thermal transfer ribbon 21 is achieved. A change in the tension of the ribbon 21 is prevented, so that an appropriate tension is always applied to the thermal transfer ribbon 21.

Now, the limiting torque of the torque limiter of the take-up reel 24 is A (torque to start sliding), the limiting torque of the torque limiter of the transport roller 25 is B, and the diameter of the winding ribbon of the take-up reel 24 is r (small diameter r1). , The diameter r2), and the pulling force of the take-up reel 24 is F (r1, r2 when r1).
At the time of F2). By the way, the following general formula is established. Fr = A (B) = constant Therefore, the following equation is established. F1r1 = F2r2 = A (B) = Constant From the previous equation, as the winding diameter r becomes larger, the tensile force F becomes larger.
Is smaller.

The change in the tension of the ribbon due to such a change in the diameter is prevented by an appropriate sliding mechanism.

The thermal transfer ribbon 21 has, along the transport direction (length direction) thereof, one frame of a receiving material coated with a pretreatment material alone for improving the adhesion of a dye, and then, for example, yellow, magenta and A total of four frames of three frames (the binder may be included in the dye) to which the dye is applied in the order of cyan are formed as one set, and a large number of sets are continuously provided.

At a position just before the printing point where the head 20 and the platen 29 are pressed into contact with each other in the direction in which the thermal transfer ribbon is conveyed, the sheet and the thermal transfer ribbon 21 are pressed in a planar manner by utilizing the waist of the curved sheet to form the thermal transfer ribbon 21. A preliminary pressing means for removing wrinkles, for example, the above-described tension roller 26 is provided.

A platen 29 is provided facing the head 20 so as to be able to press and separate.

By sandwiching the thermal transfer ribbon 21 and the sheet between the head 20 and the platen 29 at an appropriate pressure, the thermal transfer ribbon 21 is adjusted according to the conveying speed of the sheet sandwiched between the grid roller 18 and the pinch roller 19. The head 20
1 is synchronously transported from left to right in FIG. 1 to thermally transfer one frame on the thermal transfer ribbon 21. The sheet after the thermal transfer is returned from the right to the left in FIG. 1 with respect to the head 20 and the thermal transfer ribbon 21 is advanced by one frame, and then the sheet is conveyed again from the left to the right in FIG. To perform thermal transfer.

The platen 29 and the pinch roller 19 are controlled so as to be displaced in the following three stages depending on the sheet conveyance state. Receiving layer / at the time of image formation (conveying the sheet from left to right with respect to the head in the drawing) As shown in FIG.
9 is pressed against the head 20.

At this time, the pinch roller 19 is disposed at a position where the tangent at the contact point with the grid roller 18 also contacts the platen 29 so that the sheet is not broken at the pinch roller 19 portion. When the sheet is returned to the receiving layer / image formation start position (the sheet is conveyed from the right to the left with respect to the head 20). As shown in FIG. 2, the sheet being conveyed is prevented from hitting the head 20. The platen 29 is separated from the head 20 and the pinch roller 19 and the grid roller 18
Change the tangent direction at the point of contact. When a sheet is introduced into the receiving layer / image forming mechanism (the sheet is bitten between the pinch roller 19 and the grid roller 18 from the paper feed path 5) When a sheet is discharged from the receiving layer / image forming mechanism (pinch roller) The sheet is output to the paper discharge path 6 from between the area 19 and the grid roller 18).
(The platen 29 is in a separated state) to facilitate the introduction and discharge of the sheet and to prevent the jam.

The take-up reel 24 is driven by a motor 30.

Grid roller 18 and platen 29
Is driven by a first drive system including a motor 31, a belt 32, a pulley 33, and the like.

The above driving control is performed by control means (not shown) such as a CPU.

The sensor 34 determines the position at which the transfer of the thermal transfer ribbon is started. Configuration of Protective Layer Forming Mechanism 4 Next, the protective layer forming mechanism 4 will be described with reference to FIG.

At the end of the paper discharge path 6, a head 35 and a platen 36 are provided. Below that, a grid roller 37 and a pinch roller 38 are provided.

The platen 36 is separated from the head 35 when a sheet is introduced and when the thermal transfer ribbon 43 is independently conveyed.

39 is a feed reel, 40 is a take-up reel,
41 is a conveyance roller, 42 is a tension roller. Appropriate tension is applied to the thermal transfer ribbon 43 by using a torque limiter (not shown) on the transport roller 41 and the take-up reel 40.

The thermal transfer ribbon 43 is coated with a transparent material (post-processing material) for covering and protecting the surface of the sheet image.

Reference numeral 46 denotes a discharge roller for discharging the printed sheet to the discharge tray 8.

Take-up reel 40 and transport roller 41
Is driven by a motor 47.

Grid roller 37 and platen 36
Is driven by a second drive system such as a motor 48, a belt 49, and a pulley 50. The motor 4 of the second drive system
Reference numeral 8 also drives the feed roller 12, the feed roller 13, the registration roller 14, and the like in the paper feed mechanism 2 as described above.

The above driving control is performed by control means (not shown) such as a CPU. The sheet sensor 51 counts the number of printed sheets. <Operation> The operation of the above apparatus will be described with reference to FIGS. 1 to 4 and a time chart of FIG. By holding one sheet between the separation gate 11 and the paper feed tray 9, the height of the separation gate 11 is adjusted. Next, the sheets are stacked and stored in the paper feed tray 9, and the alignment guide 10 is moved to align the sheet bundle in the short direction.

On the other hand, an image is input from an image scanner (not shown) to a personal computer (not shown), and the apparatus receives image processed image information and information such as the number of prints. Next, the feeding roller 12 is driven, and the separation gate 11 is moved.
Are separated into one sheet and sent out.

This sheet is separated from the feed roller 13
And skew is corrected by hitting the registration roller 14 in a stopped state. Next, the sheet is conveyed by the feed roller 13 and the registration roller 14 which sandwich the sheet, and the switching gate 1
5 and open the grid roller 18 and the pinch roller 1
9 and reach. At this time, the sheet sensor 17 counts the number of fed sheets.

This sheet is driven by a driven grid roller 1.
The paper is fed in the direction of the head while being sandwiched by the pinch roller 8 and the pinch roller 19. At this time, the platen 29 and the pinch roller 19 are at an intermediate position between FIG. 2 and FIG.
9 is the position shown in FIG. Next, the platen 29 and the pinch roller 19 are shown in FIGS.
1, the grid roller 18 is rotated in reverse to feed the sheet backward from left to right in FIG. 1, and after detecting the rear end of the sheet with the sheet sensor 17, a predetermined number of pulses are counted and the grid is counted. The roller 18 is stopped, and the position for starting the transfer of the sheet is determined. Next, the motor 30 drives the take-up reel 24 and the transport roller 25 to position the transfer start of the frame of the receiving material on the thermal transfer ribbon 21. Next, the platen 29 is attached to the sheet and the thermal transfer ribbon 21.
3 is pressed against the head 20 to obtain the state shown in FIG. Next, the take-up reel 24, the transport roller 25, and the grid roller 18 are driven to synchronously transport the thermal transfer ribbon 21 and the sheet, and the head 20 is heated in accordance with image information, and the receiving layer is formed on the surface of the sheet by thermal transfer. To form

Before the thermal transfer ribbon 21 reaches the printing point where the head 20 and the platen 29 are in pressure contact with each other, the sheet and the thermal transfer ribbon 21 are overlapped by the stiffness of the curved sheet and conveyed in a state of being pressed by the tension roller 26. Is done. Next, the platen 29 is separated and retracted from the head 20 to obtain the state shown in FIG. (10) Repeat the operation of positioning the start of thermal transfer of the sheet, positioning the start of thermal transfer of the thermal transfer ribbon, pressing the platen to the head, thermal transfer and retreating the platen away from the head three times. Magenta and cyan dyes are sequentially transferred and images such as characters and figures are printed.

While the receiving layer and the image are formed on the first sheet in this manner, the next second sheet is advanced to the position of the registration roller 14 and is kept on standby. 11 Next, the grid roller 18 and the feed roller 7 are driven to discharge the sheet from the receiving layer / image forming mechanism 3 to the sheet discharging path 6.
Through the protective layer forming mechanism 4. At this time, the platen 29 is separated from the head 20.

When the first sheet is conveyed in the paper discharge path 6 as described above, the aforementioned second sheet is conveyed to the receiving layer / image forming mechanism 3. 12 Next,
When a predetermined pulse is counted after the sheet sensor 52 detects the leading edge of the sheet, the sheet feeding is stopped and the position for starting the transfer of the protective layer is determined. 13 Next, the thermal transfer ribbon 43
Of the start of transfer of the protective layer of the head 3 of the platen 36
5, a thermal transfer, and separation and retreat of the platen 36 from the head 35 are sequentially performed to form a protective layer on the surface of the sheet image, thereby completing the business card. 14 Next, the sheet is discharged to the discharge tray 8 by the discharge roller 46.

While the receiving sheet and the image are being formed on the second sheet, the operation until the first sheet is discharged to the discharge tray 8 and the third sheet is fed. The operation to advance from the paper tray 9 to the position of the registration roller 14 is performed. <Effects of Embodiment> This embodiment has the following effects. (1) Since the heads 20 and 35 are fixed, and the platens 29 and 36 are provided so as to be able to freely contact with and separate from the heads 20 and 35, the head 2 is heated according to image information during printing.
There is no risk of print misalignment due to backlash of 0, 35,
High quality printing can be realized. (2) Since the head 20 is fixed, the thermal transfer ribbon 2 when the platen 29 and the head 20 transition to the separated state is changed.
1 is less slack, so that there is no wrinkle on the thermal transfer ribbon 21 and no uneven printing, and there is no risk of jamming or the like. (3) When the sheet is conveyed to the different paper feed path 5 and paper discharge path 6 by switchback, the contact point between the pinch roller 19 and the grid roller 18 can be displaced in a manner similar to the conveyance direction of the sheet. The sheet is smoothly conveyed without excessive force acting on the sheet. In this case, if there is sufficient conveyance force and there is no concern about skew or the like, the grid roller 18 may be replaced with a generally used rubber roller or the like. (4) When the platen 29 is in the pressed state or the separated state with respect to the head 20, the pinch roller 19 is
9, the tangent at the contact point between the pinch roller 19 and the grid roller 18 is arranged at a position in contact with the platen 29, so that the sheet does not break at the pinch roller 19. (5) Just before the printing point where the head 20 and the platen are pressed against each other, in the conveying direction of the thermal transfer ribbon 21, the tension roller 26 for applying tension to the thermal transfer ribbon 21, and the sheet and the thermal transfer ribbon 21 by utilizing the waist of the curved sheet. By pressing them in a planar manner, wrinkles of the thermal transfer ribbon 21 can be removed, and the quality of an image by thermal transfer can be improved. <Modifications> The present invention is not limited to the above embodiment, and various modifications can be made as follows.

For example, in the above embodiment, the receiving layer / image forming mechanism is shown as the first printing means, and the protective layer forming mechanism is shown as the second printing means, but the image forming mechanism and the second printing means are used as the first printing means. The printing means may be a protective layer forming mechanism.

The first printing means may be a receiving layer forming mechanism, and the second printing means may be an image / protective layer forming mechanism.

Further, in the above-described embodiment, the image forming mechanism using the dyes of yellow, magenta and cyan was described. For example, the dyes of black alone or the dyes of four colors of black in addition to yellow, magenta and cyan are used. May be used.

[0056]

According to the present invention, the following effects can be obtained.

According to the present invention, since the platen is provided so as to be able to freely contact and separate from the head with respect to the head, there is no danger of the printing being displaced by the play of the head which is heated in accordance with the image information at the time of printing. When the recording paper is conveyed to the printing press, the platen is displaced to the press-contact position and the conveyance unit is displaced to perform printing, while when the recording paper is conveyed from the conveyance unit side to the platen side, the platen is displaced to the separated position and the conveyance unit is Is displaced, and the recording paper is transported in a state where the recording paper is securely separated from the head during non-printing, so that high quality printing can be realized.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an entire apparatus according to an embodiment of the present invention.

FIG. 2 is a partial operational view of the embodiment.

FIG. 3 is a partial operational view of the embodiment.

FIG. 4 is a perspective view showing a part of the embodiment.

FIG. 5 is a flowchart showing the operation of the embodiment.

[Description of Reference Numerals] 2 sheet feeding mechanism 3 receiving layer / image forming mechanism 4 protective layer forming mechanism 9 sheet feeding tray 12 feeding roller 18 grid roller 19 pinch roller 20 head 21 thermal transfer ribbon 29 platen 31 motor 35 head 36 platen 37 grid roller 38 Pinch roller 43 Thermal transfer ribbon 48 Motor

Claims (4)

(57) [Claims] 1. A printing head, a platen displaced at least between a press-contact position and a separation position for sandwiching recording paper between the printing head, and a platen upstream or downstream of the platen. An image forming apparatus including a transport unit for reciprocating the recording paper between the head and the platen, wherein the recording paper follows the pressure contact of the platen with the head when printing the transport unit. Displacement means for displacing the conveyance direction in a direction in which the recording medium is pressed against the head, and displacing the conveyance direction in a direction in which the recording paper is separated from the head and conveyed by following the separation of the platen from the head during non-printing, When the recording paper is conveyed from the side to the conveying means side, the platen is displaced to the pressure contact position and the conveying means is displaced to perform printing, while the platen side is conveyed from the conveying means side An image forming apparatus, wherein a platen is displaced to a separation position when a recording sheet is conveyed to a recording medium, and a conveying unit is displaced. 2. A printing head for heating a thermal transfer ribbon,
A platen that is at least displaced and moved between a pressure contact position and a separation position where the thermal transfer ribbon and the recording paper are sandwiched between the head and the thermal transfer ribbon and the recording paper; and Transport means for reciprocatingly transporting the recording paper between the recording paper and the platen, synchronously transporting the superposed thermal transfer ribbon and the recording paper, and reciprocating the thermal transfer ribbon by heating the thermal transfer ribbon according to image information by the head. In an image forming apparatus for performing overprinting on recording paper, the printing unit may displace the conveyance direction in a direction in which the recording paper presses the head via a thermal transfer ribbon by following the pressing of the platen against the head during printing. At the time of printing, the recording paper follows the separation of the platen from the head, and the recording paper is separated from the thermal transfer ribbon and the head. Displacement means for displacing the platen to the press-contact position when the recording paper and the thermal transfer ribbon are transported from the platen side to the transport means side and displacing the transport means to perform printing, while performing printing from the transport means side to the platen side An image forming apparatus, comprising: displacing a platen to a separation position and displacing a conveying unit when conveying only recording paper. 3. The printing apparatus according to claim 1, wherein the printing paper is positioned such that a portion of the printing paper that is behind the platen with respect to the transport direction is pressed against the printing head by the waist of the printing paper. An image forming apparatus configured to displace a conveying unit following a displacement of a sheet. 4. A displacing means in the image forming apparatus according to claim 1, wherein the displacing position of the platen at the time of recording paper feeding and discharging is set to a second separating position between the pressing position and the separating position. An image forming apparatus configured to follow the displacement of the platen to the second separation position and to displace the conveying means.