JPH0592654A - Printer - Google Patents

Abstract

PURPOSE:To inexpensively and certainly remove the slackening of an ink sheet by moving a slackening preventing roller up and down under its own wt. or by a spring member so as to apply tension to the ink sheet. CONSTITUTION:The tension applied to an ink sheet 150 by an ink sheet slackening preventing roller 130 is set so as to become smaller than the braking force due to a back tension mechanism 154. By this constitution, when the ink sheet 150 is taken up in a slackened state, the slackening preventing roller, 130 can be pushed up in a vertical direction without drawing out the ink sheet 150 from an ink sheet supply roller 152. Therefore, the position of the slackening preventing roller 130 in this state is detected by a sensor and, by stopping the taking-up operation of the ink sheet 150, the slackening of the ink sheet 150 can be removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print for forming a color image by interposing an image-receiving paper and an ink sheet between a platen drum and a thermal head, press-contacting with the thermal head, and heat-recording on the image-receiving paper. Regarding the device.

[0002]

2. Description of the Related Art An example of the basic configuration of a conventional printing apparatus is shown in FIG.
It shows in 0.

In the printing apparatus 100, a platen drum 110 for winding the image receiving paper P, conveying and printing the image receiving paper P, a drum motor (not shown) for rotating the platen drum 110, and the image receiving paper P on the platen drum 110. A gripper 111 for fixing, an ink sheet 150 housed in an ink sheet cassette 151 detachably provided in the printing apparatus 100, and conveyed by an ink sheet motor (not shown), and an image receiving paper between the platen drum 110. P and a thermal head 120 as a means for forming an image on the image receiving paper P by applying pressure and heat through the ink sheet 150. This thermal head 12
Reference numeral 0 indicates a platen drum 11 by a thermal head pressurizing mechanism 121 operated by a head pressurizing motor (not shown).
It is configured to be pressurized to 0.

Further, as a means for feeding the image receiving paper P to the platen drum 110, a paper feed roller 161 for conveying the image receiving paper P loaded on the paper feed cassette 160,
A manual feed roller 171 for feeding paper from the manual feed stand 170 is provided, and the image receiving paper P after printing is the discharge roller 1
The sheet 81 is discharged and stacked on the sheet discharge tray 180.

Each of the above rollers is driven by a paper feeding / discharging motor (not shown) via a driving force transmitting means such as a gear or a belt, and the paper feeding roller 161 is required by a clutch (not shown). The driving force is transmitted only in such a case.

Further, the printing apparatus 100 has a hinge portion 10
3, the upper unit 101 can be opened and closed like a clam shell around the support shaft 104 of the hinge 103 as an axis. A thermal head 120 and an ink sheet cassette 151 are held on the upper unit 101.

Accordingly, with the opening operation of the upper unit 101, the thermal head 120 and the ink sheet cassette 151 are separated from the lower unit 102 while being held by the upper unit 101. A state in which the upper unit 101 is open is shown by a chain line in the figure.

The ink sheet cassette 151 is slidable along a guide rail (not shown) provided on the upper unit 101, and the ink sheet cassette 151 can be taken in and out when the upper unit 101 is open. It has become.

When the upper unit 101 is closed, the locking member 105 provided on the upper unit 101 is fitted with the locking pin 106 provided on the lower unit 102. A cover lock solenoid (not shown) for locking can be used to set the open prohibition state.

In the printing apparatus constructed as described above, the occurrence of slack in the ink sheet 150 is often taken up as a problem. The slack of the ink sheet 150 occurs when the ink sheet cassette 151 is newly set, when the thermal head 120 is depressurized, or due to electrostatic attraction induced on the ink sheet 150 to the platen drum 110. When the platen drum 110 is rotated while the ink sheet 150 is still loose, the ink sheet 150 is wound around the platen drum 110 and the ink sheet 150 is fed from the ink sheet supply roller, or in the worst case, There is a risk that the ink sheet 150 may be cut.

Further, if the printing operation is performed while the slack is generated, there is a high risk that the ink sheet 150 will be wrinkled, so that there is a problem that the print quality is significantly deteriorated.

Accordingly, it is necessary to remove the slack of the ink sheet 150 in order to prevent the occurrence of such a problem.

Conventionally, in order to remove the looseness of the ink sheet, after the power of the printing apparatus is turned on to complete the initialization, or after the reset operation is performed and the cover is opened / closed, the printing operation is performed. A number of methods have been proposed in which the ink sheet 150 is always wound up at a fixed amount at the end or immediately before the start (for example, JP-A-59-1).
50773, JP-A-60-245583,
JP-A-63-242670).

However, in this method, a certain amount of slack may not be removed because a certain amount of winding is performed regardless of the degree of slack. Further, even if the slack is not generated, the ink sheet is unnecessarily wound up, and the ink sheet is wasted.

Particularly in a color printing apparatus, a plurality of colors are formed on an ink sheet in a frame-sequential manner, and a marker for identifying the color is provided at the beginning of each color, so that the ink sheet is wound loosely. If the picking operation is repeated several times, there is a risk that the marker may overshoot the mark detection sensor.

In this case, one screen of the ink sheet, that is, three colors of yellow (Y), magenta (M), and cyan (C) by the color selection operation of the ink sheet [four colors when black (BK) is also used] It is very uneconomical because the minute ink sheet is wasted.

Several methods have been proposed to prevent such problems. For example, Japanese Patent Application Laid-Open No. 61-47281 discloses a device in which an ink sheet supply prohibiting means is provided on an ink sheet supply roller and prohibits the supply of the ink sheet when winding the slack of the ink sheet.

Further, a sensor for detecting the rotation speed of the ink sheet supply roller is provided, and after the slack winding operation is started, when the sensor detects the rotation of the supply roller, the winding operation is stopped to stop the ink sheet. A method for preventing wasteful winding is disclosed in Japanese Patent Laid-Open No. 3-4996.
No. 9 publication.

[0019]

However, in the former of the above-mentioned prior arts, a special drive means such as a solenoid must be provided as a means for prohibiting the supply of the ink sheet, and the cost increase of the apparatus is inevitable. There was a problem.

Further, in the latter case, an encoder or the like is generally used as the rotational speed detecting means of the ink sheet supply roller, and it tends to be expensive, and the circuit and control become complicated. There was a problem that cost savings were unavoidable.

Further, in the conventional printing apparatus, the loosening of the ink sheet occurs even when the thermal head is moved up and down. That is, in the initializing operation of the printing apparatus, the vertical movement is performed in order to initialize the position of the thermal head, but the thermal head presses the ink sheet against the platen drum side by this operation, so that a small amount of ink sheet is generated. It was pulled out from the ink sheet supply roller, which was a cause of slack.
Similarly, after the printing operation is completed, when the thermal head pressure release operation is performed, the slack is generated in the ink sheet, and it is necessary to always perform the slack winding operation at the start or end of the printing operation. It was

An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a printing apparatus capable of reliably removing the slack of the ink sheet at low cost.

[0023]

The above object is to provide a platen drum for winding and carrying and printing an image receiving paper, a gripper for fixing the image receiving paper on the platen drum, and a thermal head as a heating writing means. , An ink sheet having a plurality of ink surfaces sequentially formed,
In the printing apparatus, the image receiving paper and the ink sheet are interposed between the platen drum and the thermal head and pressed against the thermal head to form a color image by heat recording on the image receiving paper. It is achieved by having a slack prevention roller configured to come into contact with the ink sheet in the transport path and be vertically movable so as to apply tension to the ink sheet.

[0024]

The slack prevention roller moves up and down by its own weight or by a spring member so as to apply tension to the ink sheet. The slack prevention roller surely removes the slack in the ink sheet.

[0025]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a main part of an embodiment of the present invention.

In the figure, the ink sheet 150 is contained in an ink sheet cassette 151, and the ink sheet cassette 151 is provided with an ink sheet supply roller 152 and an ink sheet take-up roller 153, respectively.

Further, the ink sheet cassette 151 is provided with an opening 151a, and the thermal head 120 is arranged so that pressure can be applied to the platen drum 110 from this opening 151a. Similarly, the slack prevention roller 130 of the ink sheet 150 also has the opening 151a.
Is provided so as to contact the ink sheet 150.

In addition, the ink sheet supply roller 152 does not need the ink sheet 15 that is not needed when the ink sheet cassette 151 is transported or set in the printing apparatus 100.
Back-tension mechanism 1 to prevent 0 feeding
54 is provided.

On the other hand, the ink sheet take-up roller 153
Is provided with a gear 155 having a sliding clutch, and a driving force from an ink sheet drive motor 156 is supplied to the ink sheet take-up roller 153 via the gear 155.
Be transmitted to. Further, the lower unit 102 is provided with an ink sheet carrying roller 157, and this roller 157 is also provided with a gear 158 having a sliding clutch.

Here, the conveyance torque of the ink sheet 150 by the ink sheet conveyance roller 157 is set to be larger than the winding torque by the ink sheet take-up roller 153, and the conveyance speed of the ink sheet 150 is the ink sheet conveyance roller 157. It is set so as to be determined according to the transport speed of.

This is the ink sheet take-up roller 15
This is performed in order to prevent the winding speed from changing because the roller diameter of No. 3 changes with time due to the ink sheet 150 being wound. Reference numeral 159 is a support roller for holding the ink sheet 150 and maintaining the conveyance path.

2 and 3 show an example of a mounting portion of the slack prevention roller 130 of the ink sheet 150. 2 is a front view and FIG. 3 is a side view.

The slack prevention roller 130 is attached to the upper unit 101 via a support member 131. The support member 131 has a bearing member 133 for fixing the shaft of the slack prevention roller 130, a locking member 134 for locking the spring member 132, and a support member along the groove 101a provided in the upper unit 101. A restriction member 135 for sliding the member 131 is provided.

Further, the slack prevention roller 130 is provided with the spring locking member 101b provided on the upper unit 101 and the spring locking member 134 provided on the support member 131 by the spring member 132. The ink sheet 150 is biased downward and is configured to apply a tension to the ink sheet 150.

Further, a sensor 101c such as a photo interrupter provided on the upper unit 101 is provided on the support member 1
By detecting the detection piece 136 provided in 31,
The vertical movement of the slack prevention roller 130 can be detected.

Here, the ink sheet slack prevention roller 13
By setting the tension of 0 applied to the ink sheet 150 to be smaller than the braking force by the back tension mechanism 154, when the ink sheet 150 is rolled up when the ink sheet 150 is slackened, From the ink sheet supply roller 152 to the ink sheet 1
The slack prevention roller 130 can be pushed upward without drawing 50.

Accordingly, the sensor 101c detects the position of the slack prevention roller 130 when the slack of the ink sheet 150 is sufficiently removed, and the winding operation of the ink sheet 150 is stopped, so that the ink sheet supply roller 152 is driven. The slack of the ink sheet 150 can be removed without unnecessarily feeding the ink sheet 150.

When the looseness of the ink sheet 150 is rolled up, the ink sheet 15 is loosened by the loosening prevention roller 130.
Since an appropriate tension is given to 0, there is also an effect that wrinkles can be prevented from occurring in the ink sheet 150.

In this figure, the slack prevention roller 1
The spring member 132 is provided on the ink sheet 30 to give the tension to the ink sheet 150, but the spring member 132 is not necessarily required if the weight of the slack prevention roller 130 provides sufficient tension.

Therefore, in order to arrange the slack prevention roller 130 in a limited space around the thermal head 120, in order to use the slack prevention roller 130 as small as possible, FIG. As shown in FIG. 3, by providing the spring member 132, the tension can be efficiently given to the ink sheet 150. However, in any case, as described above, the tension applied to the ink sheet 150 by the slack prevention roller 130 is applied to the back tension mechanism 15.
It goes without saying that it is necessary to set it so that it is smaller than the braking force by 4.

4 to 6 show the operation of the slack winding operation of the ink sheet 150.

In FIG. 4, since the ink sheet 150 is slack, the slack prevention roller 130 is lowered to the lower limit.

When the ink sheet motor 156 is driven in this state, the slack prevention roller 130 is gradually lifted upward as the ink sheet 150 is stretched, as shown in FIG. Finally, as shown in FIG. 6, the ink sheet motor 156 is lifted up until the slack prevention roller 130 is detected by the sensor 101c.
Is stopped, and the ink sheet 150 is transferred to the platen drum 11
It is set apart from 0.

As described above, in the conventional printing apparatus, the ink sheet 15 is moved even when the thermal head 120 is moved up and down.
Although a slack of 0 occurs, this problem can be solved at the same time according to the present invention.

This will be described with reference to FIGS. 7 to 9. FIG. 7 shows a state in which the ink sheet 150 is stretched by the slack prevention roller 130 so that slack does not occur, and the slack prevention roller 130 is stopped at a position detected by the sensor 101c. ..

From this state, when the thermal head 120 is initialized by, for example, a reset operation, the thermal head 120 pressurizes the platen drum 110 as shown in FIG. The tension applied to the ink sheet 150 can be absorbed by the rising of the slack prevention roller 130.

Next, as shown in FIG. 9, the thermal head 1
When the pressure release operation of 20 is performed, the slack prevention roller 130 descends and returns to the same state as in FIG. 7, so that the ink sheet 150 is not loosened.

This operation is similarly performed during the pressure releasing operation of the thermal head 120 when the printing operation is completed. That is, as shown in FIG.
As shown in FIG. 7, the slack prevention roller 130 is in a state of being lifted up more than in the normal state (FIG. 7). afterwards,
When the printing operation is completed, as shown in FIG. 9, the pressure release operation of the thermal head 120 is performed, and the slack prevention roller 130 descends to impart tension to the ink sheet 150 and automatically suppress the occurrence of slack. Be done.

Therefore, according to this embodiment, the slack of the ink sheet 150 caused by the pressure release operation of the thermal head 120 can be automatically absorbed by the slack preventing roller 130. There is an advantage that it is not necessary to perform the slack winding operation and the operation control can be simplified.

Here, some points to be noted in order to achieve the purpose of the operation of this embodiment described above will be described.

First, as shown in FIG. 7, the slack prevention roller 130 must be disposed between the ink sheet conveying roller 157 and the support roller 159. This is because when the slack prevention roller 130 is placed, for example, between the ink sheet supply roller 152 and the support roller 159 or between the ink sheet take-up roller 153 and the ink sheet transport roller 157, the ink sheet supply roller 152. The diameter of the take-up roller 153 and the take-up roller 153 change according to the printing operation.
The position of the slack prevention roller 130 in the state in which 50 is stretched also changes.

Therefore, even if the slack prevention roller 130 is stopped at a certain position by the sensor 101c, it becomes impossible to determine whether the slack of the ink sheet 150 has been removed.

On the other hand, in the arrangement position of the slack prevention roller 130 in this embodiment, the position of the slack prevention roller 130 is always irrespective of the change in the diameters of the ink sheet supply roller 152 and the ink sheet take-up roller 153. It becomes constant, and the above-mentioned problems do not occur.

Second, the stop position of the slack prevention roller 130 when the ink sheet 150 is stretched is the length of the ink sheet 150 stretched between the conveying roller 157 and the support roller 159 shown in FIG. L2)
In FIG. 8, assuming that the slack prevention roller 130 is not provided, when the thermal head 120 is pressed against the platen drum 110, the length of the ink sheet 150 stretched between the rollers (L
This means that the position must be set so that it is longer than in 1).

That is, when the thermal head 120 is pressed against the platen drum 110, the ink sheet 150 having a sufficient length is provided between the rollers so that the ink sheet 150 is not pulled out from the ink sheet supply roller 152. This means that the slack prevention roller 130 needs to be stretched.

Thirdly, as shown in FIG. 2 and FIG.
This means that the slack prevention roller 130 must be configured so as to be able to move further above the position where it is detected by the sensor 101c and stopped.

With this structure, even if tension is applied to the ink sheet 150 by the pressing operation of the thermal head 120, the slack prevention roller 130 moves upward and absorbs this tension. The ink sheet 150 is not fed out from the sheet supply roller 152.

Next, a control method for performing the slack winding operation of the ink sheet 150 will be described. First,
When the slack winding operation is performed, the detection state of the sensor 101c is first checked, and the ink sheet 150 is controlled to be wound only when the sensor 101c is not detecting the slack prevention roller 130. Is desirable.

That is, since the ink sheet 150 is already stretched when the sensor 101c is in the detection state,
In this case, by controlling so that the slack winding operation is not performed, an extra operation can be omitted, so that the printing efficiency can be improved.

If the sensor 101c does not detect the slack prevention roller 130 even after the ink sheet 150 has been wound up for a predetermined time, the ink sheet is stopped by an error state. It is possible to prevent problems such as cutting of the ink sheet 150 when the sheet 150 is jammed or when it is wound around the platen drum 110.

This shows that the slack prevention roller 130 can also be used as a jam sensor for the ink sheet 150.

As described above, according to this embodiment, by providing the slack prevention roller 130 in the printing apparatus, various effects can be obtained, and the slack of the ink sheet 150 can be reliably removed with an inexpensive structure. Therefore, it is possible to obtain a great effect such as waste of the ink sheet 150.

[0064]

According to the inventions of claims 1 and 2,
In contact with the ink sheet in the ink sheet transport path,
By providing the ink sheet slack preventing roller configured to apply tension to the ink sheet by its own weight, it is possible to apply the required tension to the ink sheet without providing a special pressurizing means, and to prevent the roller from displacing. The effect that uniform tension can be applied to the ink sheet regardless of the cost can be realized at low cost.

According to the third aspect of the present invention, it is provided in the upper unit of the printing device so as to be movable up and down through a spring member so as to contact the ink sheet in the ink sheet conveying path and to apply tension to the ink sheet. By providing the ink sheet slack prevention roller, the necessary tension can be efficiently applied to the ink sheet even if the slack prevention roller is made as small as possible, so that the roller is placed in a limited space around the thermal head. Can be provided, and the slack of the ink sheet can be reliably removed.

According to the fourth aspect of the present invention, the tension applied to the ink sheet by the slack prevention roller is smaller than the braking force by the braking means provided to provide the ink sheet supply roller with the back tension. By setting to (4), it is possible to prevent the ink sheet from being pulled out from the ink sheet supply roller by the tension of the slack prevention roller, and thus it is possible to prevent wasteful consumption of the ink sheet.

According to the fifth aspect of the present invention, by providing the detecting means for detecting the vertical position of the slack prevention roller that moves up and down, the position of the slack prevention roller is detected to determine whether or not there is slack. Since it can be easily discriminated, the slack prevention roller can be applied as a slack detecting means for the ink sheet.

According to the sixth aspect of the present invention, the slack of the ink sheet is detected when the slack prevention roller detecting means detects the slack prevention roller during the winding operation for removing the slack of the ink sheet. By ending the winding operation, it is possible to reliably prevent waste of the ink sheet due to excessive winding.

According to the seventh aspect of the invention, the detecting means detects the slack preventing roller within a predetermined time during the winding operation for removing the slack of the ink sheet or the color selecting operation of the ink sheet. In case of failure, by controlling to stop the ink sheet winding drive,
By using the slack prevention roller as a jam sensor for the ink sheet, it is not necessary to provide a new sensor, and it is possible to quickly deal with a problem such as cutting of the ink sheet or winding around the platen drum.

According to the invention described in claim 8, the printing apparatus is provided with a plurality of support rollers for maintaining the conveyance path of the ink sheet, and the slack prevention roller is provided between the plurality of support rollers. Since the relationship between the position of the slack prevention roller and the degree of slack of the ink sheet is constant without being affected by changes in the winding diameters of the ink sheet supply roller and the take-up roller, the slack removal operation of the ink sheet can be reliably performed. Can be done.

According to the invention described in claim 9, the stop position of the slack prevention roller when detected by the detection means of the slack prevention roller, the length of the ink sheet stretched between the support rollers is at least the thermal head. The ink sheet is pulled out from the ink sheet supply roller when the thermal head is pressed by setting the position so that it becomes longer than the length of the ink sheet stretched between the support rollers when the platen drum is pressed. Since it is possible to remove the slack of the ink sheet without waste, it is possible to prevent waste of the ink sheet.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of a printing apparatus according to an embodiment of the present invention.

FIG. 2 is a front view of a mounting portion of a slack prevention roller.

FIG. 3 is a side view of a mounting portion of a slack prevention roller.

FIG. 4 is a schematic view showing a slack winding operation of an ink sheet.

FIG. 5 is a schematic diagram showing a slack winding operation of an ink sheet.

FIG. 6 is a schematic diagram showing a state of a slack winding operation of an ink sheet.

FIG. 7 is a schematic diagram showing an arrangement condition of a slack prevention roller.

FIG. 8 is a schematic diagram showing an arrangement condition of a slack prevention roller.

FIG. 9 is a schematic diagram showing an arrangement condition of a slack prevention roller.

FIG. 10 is a basic configuration diagram of a printing apparatus according to a conventional example.

[Explanation of symbols]

 101c sensor 110 platen drum 111 gripper 120 thermal head 130 slack prevention roller 132 spring member 150 ink sheet 151 ink sheet cassette 152 ink sheet supply roller 153 ink sheet take-up roller 157 ink sheet transport roller

Claims (9)

[Claims] 1. A platen drum for winding and carrying and printing an image receiving paper, a gripper for fixing the image receiving paper to the platen drum, a thermal head as a heating and writing means, and a plurality of ink surfaces sequentially. A color image by having the formed ink sheet, press-contacting with the thermal head with the image receiving paper and the ink sheet interposed between the platen drum and the thermal head, and heat recording on the image receiving paper. In the printing apparatus for forming a sheet, there is provided a slack prevention roller configured to come into contact with the ink sheet in a conveyance path of the ink sheet and to be movable up and down so as to apply tension to the ink sheet. 2. The printing apparatus according to claim 1, wherein the slack prevention roller is provided so as to be vertically movable by its own weight. 3. The printing apparatus according to claim 1, wherein the slack prevention roller is provided in an upper unit of the apparatus main body via a spring member. 4. The tension applied to the ink sheet by the slack prevention roller according to claim 2 or 3, is also reduced by a braking force provided by a brake unit provided to apply a back tension to the ink sheet supply roller. A printing device characterized by being set as follows. 5. The printing apparatus according to claim 1, further comprising detection means for detecting the vertical position of the slack prevention roller. 6. The slack winding operation of the ink sheet according to claim 5, when the detection unit detects the slack prevention roller during execution of the winding operation for removing the slack of the ink sheet. A printing apparatus having a control unit for terminating the printing. 7. The detecting device according to claim 5, wherein the detection unit causes the slack prevention roller to move within a predetermined time during a winding operation for removing slack of the ink sheet or a color selecting operation of the ink sheet. The printing apparatus is characterized in that, when no detection is made, the control means controls to stop the winding drive of the ink sheet. 8. The apparatus according to claim 5, wherein a plurality of support rollers for maintaining the conveyance path of the ink sheet are provided, and the slack prevention roller is arranged between the plurality of support rollers. Printing equipment. 9. The stop position of the slack preventing roller when detected by the detecting means according to claim 8,
At a position where the length of the ink sheet stretched between the support rollers is at least longer than the length of the ink sheet stretched between the support rollers when the thermal head is pressed against the platen drum. A printing device characterized by being set.