JP2007301868A - Printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer which enables printing of a high precision by preventing slipping of a label in printing. <P>SOLUTION: The printer comprises a conveyance part 30 which winds off a printing paper L from a printing roll and conveys to the downstream, and a printing part 30 which carries out printing to the printing paper L sent out from the conveyance part 30. The printing part 30 is equipped with a printing head 51 opposed to the printing paper L, and a platen roller 52 which holds the printing paper L between the printing head 51 and the platen roller and sends out the printing paper L to the downstream. The conveyance part 30 is equipped with a driving pulley 33 which drives rotating, a following pulley 34 which rotates following the rotation of the driving pulley 33, a conveyance belt 31 wound around both pulleys 33 and 34, and a pressing roller 35 which holds the printing paper L between the outer peripheral face of the conveyance belt 31 and the pressing roller between the pulleys 33 and 34. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a printer in which a print head is in pressure contact with a platen roller that is driven to rotate via print paper.

  The platen roller that is in pressure contact with the print head not only enables printing by the print head, but also carries the printing paper. However, since the platen roller makes line contact with the paper, when the paper is fed by the platen roller, the platen roller may slip with respect to the printing paper. For this reason, variations occur in the print start position and print length, and the accuracy of the print position decreases. In particular, in the case of a large and high-speed printer, the label width is large and the inertia of the printing roll is large, so that it is easy to slip.

  Therefore, a method of applying a conveying force to the paper at two locations by a pair of rubber rollers is also employed. However, a stable conveying force has not been obtained.

The following patent documents 1 to 3 are known as prior arts of printers.
Shokai Sho 16-16336 (front page) JP 2000-255534 (Abstract) JP 2000-137467 (Abstract)

In the invention of Patent Document 1, the bulge portion of the head is brought into contact with the drive belt, and the label paper is brought into close contact with the head.
In the invention of Patent Document 2, a flat belt is wound between the platen roller and the auxiliary rotating shaft to prevent the glue surface of the label paper from sticking to each member.
The invention of Patent Document 3 makes it unnecessary to adjust the position between the print head and the roller by pressing the heating element of the head against a belt wound between the main driving roller and the driven roller.

  Accordingly, an object of the present invention is to provide a printer that can prevent inadvertent slipping of a label in a printing unit and can perform high-precision printing even if the conveyance speed of the label is increased.

  In order to achieve the above object, a printer of the present invention includes a transport unit that unwinds a print sheet from a print roll and transports the print sheet downstream, and a print unit that performs printing on the print sheet sent from the transport unit. In the printer, the print unit includes a print head facing the print sheet, and a platen roller that sandwiches the print sheet between the print head and sends the print sheet downstream, and the transport unit includes: A drive pulley that rotates, a driven pulley that rotates as the drive pulley rotates, a conveyor belt wound around the pulleys, and an outer peripheral surface of the conveyor belt between the pulleys. And a pressing roller for sandwiching the printing paper.

  According to the present invention, since the printing paper is sent from the transport unit to the printing unit by the driving force, inadvertent slip in the printing unit is unlikely to occur. In particular, since the pressing roller contacts the outer peripheral surface of the conveying belt between both pulleys via the printing paper, the conveying belt and the printing paper are in contact on a wide surface, so that the inertia is large in the case of a large-diameter printing roll. However, the printing paper can be reliably sent to the printing unit. Therefore, the inadvertent slip can be surely prevented. As a result, high-precision printing is possible even when high-speed printing is performed.

The present invention further includes an auxiliary roller that rotates together with the pressing roller, and a pressing belt that is wound around the pressing roller and the auxiliary roller and sandwiches the printing paper between the conveyance belt. Is preferred.
According to this aspect, the contact surface between the conveyance belt and the printing paper is further widened by the pressing belt contacting the conveyance belt via the printing paper.

In the present invention, it is preferable that the conveyance speed by the platen roller is set to be higher than the conveyance speed by the conveyance belt.
According to this aspect, it is possible to prevent the printing paper from loosening between the platen roller and the conveyance belt. Note that the force for pinching the printing paper between the conveying belt and the pressing roller can be made larger than the force for the platen roller and the print head to pinch the printing paper, so the speed difference causes the printing paper to slip at the printing portion. Is acceptable. In this case, the printing paper slips with respect to the platen roller, but the printing paper conveyance speed is equal to the circumferential speed of the conveyance belt, so that the printing paper feeding speed can be kept at a predetermined value.

In the present invention, a first toothed pulley that is rotationally driven by a motor is connected to the drive pulley, a second toothed pulley is connected to the driven pulley, and the pair of toothed pulleys are toothed. The belt is preferably wound.
According to this aspect, since the driving force is transmitted via the pair of toothed pulleys and the toothed belt, the conveyance amounts coincide at the time of feeding and the time of back feeding. Therefore, the accuracy when printing after backfeeding is improved.

In the present invention, it is preferable that the printing paper is a label, and a label sensor for detecting a front end and / or a rear end of the label is further provided between the printing unit and the transport unit.
According to this aspect, when the printing unit performs printing based on the detection information by the label sensor, it is possible to ensure the printing position accuracy with respect to the label.

Embodiments of the present invention will be described below with reference to the drawings.
1 and 2 show Example 1. FIG.

Schematic configuration:
As shown in FIG. 1A, the label printer 1 includes a printing roll Lr, a damper 20, a transport unit 30, a label sensor 40, a printing unit 50, and a ribbon supply unit 60.

  The printing roll Lr is formed by, for example, winding a strip-shaped printing paper L around a paper tube Lc. As shown in FIG. 1 (b), the printing paper L is composed of a number of labels L1 coated with an adhesive on the back surface and a strip-shaped mount L2 on which the labels L1 are temporarily attached. Adjacent labels L1 are temporarily attached to the mount L2 with a slight interval Δ therebetween.

  As shown in FIG. 1A, the printing roll Lr has the paper tube Lc fitted on the outer periphery of a bobbin 10 that is rotatably provided with respect to the plate frame 70 of the label printer 1. Loaded.

  The printing paper L unwound from the printing roll Lr is guided to the transport unit 30 via the damper 20. The conveyance unit 30 sends the printing paper L to the printing unit 50.

  A label sensor 40 is provided between the conveyance unit 30 and the printing unit 50. The label sensor 40 is composed of, for example, an optical sensor, and detects the front end Lf and the rear end Lb of the label L1 shown in FIG.

  In FIG. 2, the label sensor 40 includes a light projecting unit 41 and a light receiving unit 42. The light emitted from the light projecting unit 41 passes through the printing paper L and is detected by the light receiving unit 42. The label sensor 40 detects the end portions Lf and Lb of the label L1 shown in FIG. 1B based on the change in the amount of transmitted light detected by the light receiving unit.

  The printing unit 50 shown in FIG. 1A includes a print head 51 and a platen roller 52, and the print paper L is supplied between the print head 51 and the platen roller 52. The printing paper L is conveyed at a predetermined speed in the printing unit 50 by a platen roller 52 that is rotationally driven by a motor (not shown).

  On the other hand, a ribbon supply unit 60 for supplying the ink ribbon 62 is provided above the print head 51 shown in FIG. The ribbon supply unit 60 includes an unwinding roller 63 on which a ribbon roll 61 is loaded and a winding roller 64. The ink ribbon 62 is unwound from the ribbon roll 61 loaded on the unwinding roller 63 and supplied to the printing unit 50. The ink ribbon 62 is supplied in the printing unit 50 so as to be in close contact with the upper surface of the label L1.

  Due to the heat generated by the print head 51, a predetermined portion of the ink ribbon 62 is thermally transferred to the print surface Ls of the label L1, whereby printing is performed on the print surface Ls of the label L1. The printing position on the printing surface Ls is determined based on the front end Lf of the label L1 detected by the label sensor 40.

  The printed printing paper L is discharged from the label printer 1 to the outside of the label printer 1. On the other hand, the printed ink ribbon 62 is taken up by the take-up roller 64.

Next, the main part of the present invention will be described.
Transport unit 30:
As shown in FIG. 2, the transport unit 30 includes a transport belt 31 that is in close contact with the lower surface of the print paper L, and a pressing belt 32 that is in close contact with the upper surface of the print paper L. Both belts 31 and 32 are endless flat belts, respectively, and the printing paper L is sandwiched between the belts 31 and 32 and conveyed in the conveyance direction X.

  The conveyance belt 31 is disposed between a drive pulley (drive belt wheel) 33 provided on the downstream side in the conveyance direction X of the printing paper L and a driven pulley (driven belt wheel) 34 provided on the upstream side. It is wound. The drive pulley 33 is rotated by the motor (not shown). The driven pulley 34 is provided so as to be rotatable with respect to the plate-like frame 70 of FIG.

  On the other hand, the pressing belt 32 in FIG. 2 is wound between a pressing roller 35 provided on the upstream side along the conveyance direction X of the printing paper L and an auxiliary roller 36 provided on the downstream side. The pressing roller 35 and the auxiliary roller 36 are provided so as to be rotatable with respect to the plate-like frame 70 (FIG. 1A). As shown in FIG. 2, the pressing roller 35 is provided between the drive pulley 33 and the driven pulley 34, and circumscribes the driven pulley 34 via a pair of belts 31 and 32 and the printing paper L. ing.

  When the drive pulley 33 is driven to rotate in the forward direction indicated by the arrow in FIG. 2 by the motor, the contact surface of the transport belt 31 with the print paper L moves in the transport direction X, and the label of the pressing belt 32 The contact surface on the L1 side moves in the transport direction X, and the printing paper L is sent out toward the printing unit 50.

  As described above, since the printing paper L is sent out from the transport unit 30 to the printing unit 50 by the driving force, slip in the printing unit 50 hardly occurs. In particular, since the pressing roller 35 contacts the outer peripheral surface of the conveyance belt 31 between the pulleys 33 and 34 via the printing paper L, the conveyance belt 31 and the printing paper L come in contact with each other on a wide surface. Even if the inertia of the printing roll Lr is large, the printing paper L can be reliably sent out to the printing unit 50. Therefore, the slip can be reliably prevented. As a result, high-precision printing is possible even when high-speed printing is performed.

Transport speed;
Here, the platen roller 52 of the printing unit 50 and the drive pulley 33 are rotationally driven by the same motor. By attaching deceleration means (not shown) to the motor, the peripheral speed of rotation of the drive pulley 33 is set to a value smaller than the peripheral speed of rotation of the platen roller 52. That is, the conveyance speed of the printing paper L is set to be higher than the conveyance speed of the platen roller 52 than that of the conveyance belt 31.

  In this way, the conveyance speed of the printing paper L by the downstream platen roller 52 (the peripheral speed of the platen roller 52) is set larger than that of the upstream belts 31 and 32 (the peripheral speed of the belts 31 and 32). Therefore, the printing paper L can be prevented from loosening between the printing unit 50 and the conveyance unit 30 due to the speed difference. In particular, since the end portions Lf and Lb of the label L1 are detected by the label sensor 40 between the transport unit 30 and the printing unit 50, the printing position accuracy with respect to the label L1 is prevented by preventing the printing paper L from slackening. Etc. can be secured.

  The force for sandwiching the printing paper L between the conveyance belt 31 and the pressing belt 32 is set to a value larger than the force for the platen roller 52 and the printing head 51 to sandwich the printing paper L. For this reason, the printing paper L can be prevented from slackening due to the speed difference between the transport unit 30 and the printing unit 50, and the printing paper L slips between the platen roller 52 and the thermal head 51 in the printing unit 50. Accordingly, an unnecessarily large force is not applied to the printing paper L between the transport unit 30 and the printing unit 50.

FIG. 3 shows a second embodiment.
Mismatch in the transport amount of the printing paper L;
Here, when transporting in the normal rotation direction X1, the transport belt 31 indicated by a two-dot chain line in FIG. 3A is driven by a drive pulley 33 on the downstream side of the pair of pulleys 33 and. When feeding the printing paper L in the forward rotation direction X1, the drive pulley 33 rotates to pull the belt surface 31c of the feeding belt 31 in contact with the printing paper L toward the downstream side X1. On the other hand, at the time of back feed in which the printing paper L is transported in the direction X2 opposite to the forward rotation direction X1, the drive pulley 33 rotates in the reverse direction so as to push the belt surface 31c of the transport belt 31 toward the upstream side X2. Otherwise, the conveyor belt 31 may be loosened. Therefore, the tension of the belt surface 31c of the conveyance belt 31 that contacts the printing paper L does not match between the feed time and the back feed time. Accordingly, since the transport amount of the printing paper L does not match at the time of feeding and back feeding, the accuracy of the printing position is reduced when printing is resumed after back feeding.

Therefore, in the second embodiment, the conveyance amount of the printing paper L at the time of feeding and at the time of back feeding is matched by using the following configuration.
As shown in FIG. 3A, a first toothed pulley 33a and a second toothed pulley 34a are provided on the back side of the plate-like frame 70 (FIG. 1A). The first and second toothed pulleys 33a and 34a are connected to the driving pulley 33 and the driven pulley 34, respectively. That is, the first toothed pulley 33a and the drive pulley 33 are fixed on the same axis of the first rotating shaft 33s. On the other hand, the second toothed pulley 34a and the driven pulley 34 are fixed on the same axis of the second rotating shaft 34s.

  As shown in FIG. 3 (b), between the first toothed pulley 33a and the second toothed pulley 34a, an endless toothed belt 31a that meshes with the unevenness of the two toothed pulleys 33a, 34a is provided. It is wound.

  When the first toothed pulley 33a is rotationally driven by the drive motor M shown in FIG. 3A via the speed reduction means 39, the second toothed pulley 34a is rotated in conjunction with the toothed belt 31a. Is done. Due to the meshing transmission by the toothed belt 31a, the second toothed pulley 34a is rotationally driven in conjunction with the first toothed pulley 33a regardless of forward and reverse rotation of the first toothed pulley 33a.

  Since the driving pulley 33 and the driven pulley 34 are connected to the first toothed pulley 33a and the second toothed pulley 34a, the tension of the conveying belt 31 is constant regardless of the time of feeding and back feeding. . Therefore, the occurrence of slack in the transport belt 31 is prevented, thereby preventing the accuracy of the printing position from being lowered.

  Other configurations are the same as those in the first embodiment, and the same reference numerals are given to the same or corresponding portions, and detailed description thereof is omitted.

FIG. 4 shows a third embodiment.
As shown in FIG. 4, the printer of the third embodiment is provided with a pressing roller 35 </ b> A that is in contact with the conveyance belt 31 via the printing paper L. The pressing roller 35 </ b> A is provided between the driving pulley 33 and the driven pulley 34, and sandwiches the printing paper L between the outer peripheral surface of the conveyance belt 31.
Other configurations are the same as those in the first embodiment, and the same reference numerals are given to the same or corresponding portions, and detailed description thereof is omitted.

By the way, when printing is performed, if dirt such as dust adheres to the printing surface Ls of the label L1 shown in FIG. 1B, printing cannot be performed on the dust-attached portion. It becomes.
Therefore, in the label printer of this embodiment, the pressing belt 32 of FIG. 1 is made of an adhesive material that does not peel off the label L1 attached to the mount L2. Therefore, it is possible to maintain good print quality by attaching dust or the like to the pressing belt 32 and removing the dirt on the print surface Ls of the label L1 before printing.
On the other hand, in the third embodiment shown in FIG. 4, the surface of the label L1 can be removed by employing, for example, a rubber roller as the pressing roller 35A.
In this way, it is not necessary to separately provide a device for cleaning the surface of the label L1 by removing the dirt on the surface of the label L1 by the pressing belt 32 and the pressing roller 35A. Print quality can be obtained.

As described above, the preferred embodiments have been described with reference to the drawings. However, those skilled in the art will readily understand various changes and modifications within the obvious scope by looking at the present specification.
For example, in each of the above-described embodiments, the printing roll in which the label is wound outward is described as an example. However, a printing roll in which the label is wound inward of the printing roll may be used. Further, it may be a printing paper without a mount.
Accordingly, such changes and modifications are to be construed as within the scope of the invention as defined by the claims.

  This apparatus can be used in a printer that performs printing on printing paper.

1A is a schematic side view showing a printer according to a first embodiment of the present invention, and FIG. 1B is a schematic plan view showing an example of printing paper used in the printer. It is a schematic side view showing the conveyance unit and the vicinity of the printing unit. (A) is a schematic plane sectional view which shows the conveyance part concerning Example 2 of this invention, (b) is a schematic side view which shows a conveyance part and the printing part vicinity. It is a schematic side view which shows the conveyance part concerning Example 3 of this invention, and the printing part vicinity.

Explanation of symbols

1: Label printer 30: Conveying unit 31: Conveying belt 31a: Toothed belt 32: Pressing belt 33: Driving pulley 33a: First toothed pulley 34: Driven pulley 34a: Second toothed pulley 35, 35A: Pressing Roller 36: Auxiliary roller 40: Label sensor 50: Printing section 51: Print head 52: Platen roller L: Printing paper L1: Label Lr: Printing roll

Claims (5)

A printer comprising a conveyance unit that unwinds printing paper from a printing roll and conveys the printing paper downstream, and a printing unit that performs printing on the printing paper fed from the conveyance unit,
The print unit includes a print head facing the print paper, and a platen roller that sandwiches the print paper between the print head and sends the print paper downstream.
The transport unit includes a drive pulley that rotates, a driven pulley that rotates as the drive pulley rotates, a transport belt wound around the pulleys, and an outer peripheral surface of the transport belt between the pulleys. And a pressing roller for sandwiching the printing paper therebetween.   2. The printer according to claim 1, further comprising: an auxiliary roller that rotates together with the pressing roller; and a pressing belt that is wound around the pressing roller and the auxiliary roller and sandwiches the printing paper between the conveyance belt.   The printer according to claim 1 or 2, wherein the transport speed by the platen roller is set to be higher than the transport speed by the transport belt.   4. The first toothed pulley rotated by a motor is connected to the drive pulley, and the second toothed pulley is connected to the driven pulley. A printer with a toothed belt wound around a pulley.   5. The printing paper according to claim 1, further comprising a label sensor that detects a front end and / or a rear end of the label between the printing unit and the transport unit. Printer.

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