JP3743157B2 - Printer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a printer mounted on a POS terminal or the like capable of printing on roll paper. More specifically, the present invention relates to a printer capable of preventing the roll paper from being bent toward the print head at a print position by the print head.
[0002]
[Prior art]
A POS terminal or the like is generally equipped with a printer for printing on roll paper. An ink jet head, a wire dot head, or a thermal head is used as the print head of the printer.
[0003]
Among such printers, there are known printers that can perform printing on cut paper as well as roll paper, and are disclosed in, for example, Japanese Patent Laid-Open No. 5-147284. In a printer that prints on both roll paper and cut paper, it is desirable to use a common drive motor as a drive source for both transport mechanisms from the viewpoint of miniaturization and compactness. A mechanism for switching and transmitting rotation to different transport mechanisms using a common drive motor is disclosed, for example, in JP-A-1-249472.
[0004]
On the other hand, in printers that print on roll paper, roll paper loading that opens and closes the open / close lid that opens and closes the roll paper loading section formed on the printer body so that roll paper can be easily replaced or loaded. A mechanism has been proposed. For example, Japanese Patent Publication No. 6-79855 proposes a recording apparatus having such a roll paper loading mechanism. In the recording apparatus disclosed herein, a platen roller (roll paper feed roller) pressed against the thermal head is also attached to the tip of a cover that functions as an open / close lid of the roll paper loading unit. By fully opening the cover, the roll paper can be easily attached to the roll paper loading unit. Further, since the platen roller is also separated from the thermal head by opening the cover, the roll paper unwinding portion can be easily arranged between the platen roller and the thermal head. Furthermore, by closing the cover, a state in which roll paper is sandwiched between the thermal head and the platen roller can be automatically formed.
[0005]
[Problems to be solved by the invention]
When using an inkjet head or a wire dot head as a print head in a printer configured as described above for printing on roll paper, unlike a thermal head, there is a certain gap between the head and the print surface of the roll paper. Need to form.
[0006]
If this gap fluctuates, the print quality may be reduced. Further, when the print surface of the roll paper comes into contact with the head, the print surface is stained with ink or the like. Furthermore, there is a possibility that the roll paper jams at the print position by the head.
[0007]
However, since the roll paper is wound in a roll shape, the roll paper unwound from the roll paper has a curl and is curved in a direction perpendicular to the paper surface of the roll paper. Therefore, even if the gap between the print head and the platen roller can be kept constant, the roll paper conveyed through the print head tends to bend in a state of protruding toward the print head. There is a risk that the gap may not be maintained at the proper dimensions.
[0008]
Here, during the conveyance of the roll paper, since the roll paper is always pulled with a predetermined force in the conveyance direction by the platen roller (roll paper feed roller), the degree of the curvature of the roll paper is small, and the adverse effects caused thereby. Doesn't matter so much.
[0009]
However, when the conveyance of the roll paper is stopped, the platen roller connected to the final stage is slightly back and forth due to the backlash of the gear train for transmitting the rotational force from the drive motor to the platen roller. Becomes freely rotatable. Further, when the drive motor is stopped and the hold current is turned off to reduce heat generation, the gear train connected to the drive motor is easily rotatable.
[0010]
In such a state, the platen roller connected to the last stage of the gear train becomes rotatable, and the tensile force acting on the roll paper conveyed through the roller is released. As a result, the roll paper loosens due to curl or the like attached to the roll paper, and rises from the platen roller. As a result, the roll paper near the platen roller is greatly curved toward the print head, and the roll paper may come into contact with the print head. As a result, ink stains occur on the surface of the roll paper, or when the roll paper is resumed in a largely curved state, the roll paper may jam at the position of the print head.
[0011]
In the printer configured to switch the rotation of the common drive motor to the roll paper transport mechanism and the cut paper transport mechanism by the switching means and transmit the rotation of the roll paper, the switching means is switched to the cut paper transport mechanism. It also occurs in the case of. This is because the gear train constituting the roll paper transport mechanism is rotatable by this switching, so that the platen roller connected to the final stage is rotatable.
[0012]
In view of this point, an object of the present invention is to propose a printer capable of avoiding adverse effects such as the roll paper being bent and contacting the print head side even when the roll paper is not conveyed. .
[0013]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a drive motor, a roll paper feed roller, a cut sheet feed roller, and a roll paper feed gear train for transmitting the rotation of the drive motor to the roll paper feed roller. And a cut paper transport gear train for transmitting the rotation of the drive motor to the cut paper feed roller, and a roll paper drive position and the cut paper capable of transmitting the rotation of the drive motor to the roll paper transport gear train A switching means having a switching gear movable between a cut sheet drive position that can be transmitted to the feed roller, and a gear included in the roll paper transporting gear train for restraining free rotation Rotation restricting means for applying a braking force, and tension applying means capable of applying a tensile force in the transport direction to the print surface portion of the roll paper transported via the print position by the print head. It is said.
[0014]
Thus, at least one gear included in the gear train is given a braking force by the rotation restraining means and its free rotation is restricted. Therefore, even when the drive motor is stopped, the gear does not rotate substantially because the braking force is applied to the gear. As a result, the roll paper feed roller connected to the last stage of the gear train including the gear does not rotate. Therefore, the roll paper is held in a state in which a predetermined tensile force is applied, as in the conveyance state, and there is no problem that the roll paper is bent and contacts the print head side.
[0016]
In the printer of this configuration, when the rotation transmission of the drive motor is switched to the cut paper transport gear train side, the braking force is acting on the gear included in the roll paper transport gear train, The rotation of the roll paper feed roller connected to the gear train is also restricted. Therefore, since the tensile force acting on the roll paper is not released, the roll paper does not float to the print head side.
[0017]
On the other hand, not only does the roll paper bend toward the print head and prevent it from coming into contact with the print head, but also positively applies a tensile force to the roll paper to keep the gap between the print head and roll paper constant. It is desirable to be able to hold it. For this purpose, in addition to the above-described configuration, a tension applying means capable of applying a tensile force toward the transport direction may be added to the print portion of the roll paper transported via the print position by the print head. .
[0018]
Here, when the present invention is applied to a printer having a configuration in which the opening / closing lid of the roll paper loading unit can be fully opened, a roll paper loading unit into which the roll paper is loaded and an opening / closing lid for opening / closing the roll paper loading unit are provided. The roll paper feed roller is moved to an operating position and a retracted position in conjunction with opening and closing of the opening / closing lid, and the roll paper feed roller is in the operating position using the tension applying means. In this case, a tensile force may be applied to the print surface portion of the roll paper, and the tensile force may be released when the roll paper feed roller is in the retracted position.
[0019]
In this case, the roll paper feed roller is attached to the open / close lid, and the open / close lid is attached with a paper guide for guiding the roll paper toward the roll paper feed roller. The print portion of the roll paper can be bridged between the paper guide and the roll paper feed roller.
[0020]
As described above, in the printer configured to move the roll paper feed roller, the roll paper transport gear train includes a gear that rotates integrally with the roll paper feed roller, and the gear that is directly meshed with the gear. It is preferable that the braking force is applied by the rotation restraining means.
[0021]
That is, since the rotation restraining means is disposed to restrain the roll paper feed roller from rotating, it is desirable to apply a braking force to the gears near the roll paper feed roller as much as possible. However, in the configuration in which the roll paper feed roller moves together with the opening / closing lid, the gear that rotates integrally with the roll paper feed roller moves integrally with the roll paper feed roller, so that a stable braking force is applied to the gear. It may be difficult to construct. Therefore, as in the present invention, if a braking force is applied to a gear that meshes with the gear and is always attached to a fixed position on the printer body side, a stable braking force can be applied, and the effect Thus, the rotation of the roll paper feed roller can be restricted.
[0022]
Next, in the printer of the present invention, instead of the rotation restricting means, a rotation preventing means for preventing the rotation of the gear can be provided. In this case, the rotation prevention unit may prevent the rotation of the gear while the rotation of the drive motor is transmitted to the cut sheet conveying gear train.
[0024]
In the printer of the present invention, an ink jet head or a wire dot head can be adopted as the print head.
[0025]
Further, in this specification, the term “printing” is used as a term synonymous with “printing” and “recording”. That is, it is used as a term including not only printing of characters but also printing of other patterns, symbols, and the like.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of an ink jet printer to which the present invention is applied will be described below with reference to the drawings.
[0027]
(Overall configuration of inkjet printer)
FIG. 1 is a perspective view of an ink jet printer to which the present invention is applied, and FIG. 2 is an explanatory view showing the paper conveyance path. As shown in these drawings, the ink jet printer 1 has a roll paper loading mechanism 2 and a cut paper insertion slot 3 for inserting a cut paper of A4 size or the like, and is supplied from the roll paper loading mechanism 2. The conveyance path is configured so that the roll paper 4 and the cut sheet 5 inserted from the cut sheet insertion port 3 are respectively conveyed through a common printing position 11 (area surrounded by a one-dot chain line in the drawing). ing.
[0028]
The roll paper 4 is unwound from the roll body 4A loaded in the roll paper loading mechanism 2, passes between the paper guide 27 and the pressing roller 15, passes through the printing position 11, and passes through the platen roller (roll paper feed). Roller) 26 and the pressing roller 16 are conveyed. The roll paper 4 is conveyed by the rotation of the platen roller 26.
[0029]
On the other hand, the cut sheet 4 is inserted from the cut sheet insertion port 3, passes between the paper feed roller 51 and the driven roller 52, passes between the paper feed roller 53 and the driven roller 54, and prints position 11. And is conveyed via the paper feed roller 55.
[0030]
A guide shaft 6 is arranged in parallel at the common printing position 11, and a carriage 7 on which the ink jet head 8 is mounted can reciprocate along the guide shaft 6. Therefore, desired printing is performed by the inkjet head 8 on the surfaces of the roll paper 4 and the cut sheet 5 that pass through the common printing position 11.
[0031]
Ink is supplied to the inkjet head 8 from an ink supply unit 10 mounted at a position adjacent to the roll paper loading mechanism 2 via an ink tube (not shown).
[0032]
(Configuration of tension applying means)
Here, the roll paper 4 is unwound from the roll body 4 </ b> A wound in the roll shape loaded in the roll paper loading mechanism 2, and is conveyed via the printing position 11. Accordingly, the roll paper has a curl and the portion of the roll paper that passes through the printing position 11 tends to bend in a convex state toward the inkjet head 8. In this example, a tension applying means is provided in order to form a flat print surface portion by correcting the curvature of the portion of the roll paper passing through the print position 11, that is, the print surface portion.
[0033]
FIG. 3 is an enlarged view of the main components of the roll paper conveyance path of the inkjet printer 1 centered on the printing position 11. With reference to FIG. 3 and FIG. 2, the tension | tensile_strength provision means of this example is demonstrated.
[0034]
As shown in these drawings, the roll body 4A is supported by a pair of front and rear support rollers 13 and 14 which are disposed on the bottom surface of a roll paper loading unit which will be described later. The roll paper 4 unwound from the roll body 4A passes between the paper guide 27 and the pressing roller 15 as a pressing member, and is positioned above the convex curved surface 27a of the paper guide 27. The platen roller (roll paper feed roller) 26 is guided. Next, the roll paper 4 passes between the platen roller 26 and the pressing roller 16 pressed against the platen roller 26 and is discharged to the outside.
[0035]
Here, the portion of the roll paper 4 that is stretched between the paper guide 27 and the platen roller 26 is located at the printing position 11 by the inkjet head 8. That is, this portion of the roll paper 4 is a print surface portion 4 </ b> B on which printing is performed by the inkjet head 8.
[0036]
Although the detailed structure will be described later, the platen roller 26 and the paper guide 27 are attached to the tip of a slide frame 25 (see FIG. 6), which is a component of the opening / closing lid of the roll paper loading mechanism 2, and the slide It moves together with the frame 25. 2 and 3 show the position of the platen roll 26 and the paper guide 27 with the slide frame 25 closed, and this position is referred to herein as the “operation of the platen roller 26 as needed. Called “position”. In addition, the position of the platen roller 26 that is opened from the slide frame 25 and retracted from the operation position along with the slide frame 25 is referred to as a “retraction position”.
[0037]
When the platen roller 26 is set at its operating position, the platen roller 26 is connected to a driving force transmission mechanism (not shown) and is driven to rotate. As described above, the pressing roller 16 is pressed against the outer peripheral surface of the platen roller 26 by a certain elastic force. Accordingly, the roll paper 4 sandwiched between the rollers 26 and 16 is conveyed as the platen roller 26 rotates.
[0038]
Here, the tension applying means of this example is constituted by the pressing roller 15. The pressing roller 15 includes a rotation center shaft 15a, a roller body 15b rotatably supported by the rotation center shaft 15a, and a spring member that urges both ends of the roller rotation center shaft 15a toward the paper guide 27. 15c.
[0039]
The pressing roller 15 is pressed against the surface 27 a of the paper guide 27 with a certain elastic force at a position upstream of the print surface portion 4 B of the roll paper 4 in the transport direction. Accordingly, a tensile force acts on the roll paper 4 that passes between these and is pulled by the rotational force of the platen roller 26. That is, since the roll paper 4 is pressed against the surface 27a of the paper guide 27 with a certain elastic force, the roll paper stretched between the pressing roller 15 and the platen roller 26 by the sliding frictional resistance generated thereby. A tensile force acts on the print surface portion 4B of 4 along the transport direction.
[0040]
As a result, even if the roll paper 4 is wrinkled, the printing surface portion 4B of the roll paper 4 located at the printing position 11 by the ink jet head 8 is substantially flat because its curvature is corrected by the tensile force. It is said. Therefore, the gap between the ink jet head 8 and the printing surface portion 4B is kept constant, so that it is possible to avoid the deterioration of printing quality caused by the gap fluctuation, the occurrence of dirt on the roll paper surface, the jamming of the roll paper at the printing position, and the like. .
[0041]
The tension applying means is constituted by the paper guide 27 and the pressing roller 15. However, instead of the paper guide 27, a brake roller whose rotation is restricted by a constant braking force is used, and the pressing roller 15 is pressed against this. It is good also as a structure.
[0042]
(Driving force transmission mechanism and rotation restraint means)
Next, FIGS. 4 and 5 show a schematic configuration of the driving force transmission mechanism assembled in the printer 1 of this example. This drive force transmission mechanism transmits the rotation from a single drive motor to the roll paper transport gear train and the cut paper transport gear train via the switching means, and each platen serving as a roll paper feed roller. The roller 26 and the paper feed rollers 51, 53, and 55 for conveying cut sheets are configured to be rotationally driven. In FIG. 4, the positions of the platen roller 26 and the paper feed rollers 51, 53, and 55 are indicated by diagonal lines for easy understanding.
[0043]
Further, in the printer 1 of this example, the roll paper conveying gear train is arranged so that the tension applied to the roll paper 4 by the tension applying means is not released when the platen roller 26 is stopped. Rotation restraining means for restraining the rotation of is provided. FIG. 5 also shows a schematic configuration of the rotation restraining means.
[0044]
First, the driving force transmission mechanism will be described. The driving force transmission mechanism meshes with a single driving motor 61 and a driving gear 61a, a roll paper conveying gear train for transmitting the motor rotation to the platen roller 26, and a single sheet paper feeding roller. A cut sheet conveying gear train for transmitting to 51, 53, and 55 and a switching gear (switching means) 62 for switching to which gear train the motor rotation is transmitted are provided. This switching gear 62 is always meshed with a drive gear 61a attached to the motor output shaft.
[0045]
The roll paper gear train includes a first gear 71 that can mesh with the switching gear 62, a second gear 72 that is coaxially connected to the gear 71, and a third gear that meshes with the second gear 72. 73, and a platen roller drive gear 31 meshing with the third gear 73. The platen roller drive gear 31 is connected and fixed coaxially to the end of the rotation shaft 26 a of the platen roller 26.
[0046]
In this example, as will be described later, the platen roller 26 is attached to the tip of the slide frame 25 which is a component part of the opening / closing lid of the roll paper loading mechanism 2, and when the platen roller 26 is positioned at the operating position, The drive gear 31 attached to the rotation shaft 26 a of the platen roller 26 is in a state of being engaged with the third gear 73.
[0047]
On the other hand, the cut sheet conveying gear train includes a first gear 81 that can mesh with the switching gear 62, a second gear 82 that is coaxially connected to the first gear 81, and the second gear. A third gear 83 meshed with the second gear 82, fourth and fifth gears 84, 85 meshed with the third gear, a sixth gear 86 meshed with the fourth gear 84, And a seventh gear 87 meshing with the fifth gear. Further, a paper feed roller drive gear 88 meshed with the sixth gear 86, a paper feed roller drive gear 89 meshed with the third gear 83, and a paper feed roller drive gear meshed with the seventh gear 87. 90. The paper feed roller drive gear 88 is coaxially connected to the paper feed roller 51, the paper feed roller drive gear 89 is coaxially connected to the paper feed roller 53, and the paper feed roller drive gear 90 is coaxial to the paper feed roller 55. Linked to state.
[0048]
The switching gear 62 can move between the solid line position (roll paper drive position) and the imaginary line position (cut sheet drive position) in FIG. 5 along its rotation center axis 62a. This is performed by a drive mechanism (not shown) composed of a solenoid or the like.
[0049]
As can be seen from FIGS. 4 and 5, when the switching gear 62 is in the solid line position (roll paper drive position), the motor rotates via the first to third gears 71 to 73. The platen roller 26 is rotationally driven. As a result, the roll paper 4 is conveyed.
[0050]
When the switching gear 62 is at the imaginary line position (cut sheet drive position), the motor rotation is transferred to the paper feed roller drive gears 88, 89, 90 via the first to seventh gears 81-87, respectively. Then, the paper feed rollers 51, 53, and 55 are rotationally driven. As a result, the cut sheet 5 is transported.
[0051]
Here, as shown in FIG. 5B, a rotation restraining means is attached to the third gear 73 that is a constituent gear of the roll paper transport gear train, and a braking force that always restrains rotation is provided. It has been added. The rotation restraining means of this example includes a spacer 91 disposed between the third gear 73 and the printer main body frame 21, a brake plate 92 disposed on the other side of the third gear 73, and presses the brake plate 92. A possible pressing lever 93, a lever fulcrum member 94 supporting the middle position of the lever 93, and a coil spring 95 connected to the other end of the lever 93 are provided.
[0052]
The coil spring 95 is connected to the lever 93 in an extended state. Therefore, with the fulcrum member 94 in the middle of the lever as a fulcrum, the tip of the lever 93 presses the brake plate 92 toward the side surface of the third gear 73. Due to the lateral pressure of the brake plate 92, the third gear 73 is constantly applied with a braking force that restricts the rotation of the gear.
[0053]
As described above, in the printer 1 of this example, the braking force that restricts the rotation is always applied to the third gear 73 that is the constituent gear of the roll paper transport gear train. This braking force is not a large force that hinders the rotational drive of the platen roller 26 due to the rotation of the drive motor 61, but in a state where the rotational force is not transmitted via the roll paper transport gear train, It is set to a force sufficient to prevent the row from rotating.
[0054]
Accordingly, even when the switching gear 62 is switched to the cut sheet drive position, the rotation of the roll paper transport gear train is prevented, so that the platen roller 26 connected to the final stage does not rotate. Absent. Therefore, it can be avoided that the roll paper 4 is loosened and curved toward the ink jet head 8 so that the ink or the like adhering to the nozzle surface adheres to the roll paper surface and stains occur. That is, even when the printing on the roll paper 4 is stopped and the switching gear 62 is switched to perform printing on the cut paper 5, the tensile force applied by the tension applying means is applied to the roll paper 4 as it is. Can maintain the state of action.
[0055]
Here, the reason for applying the braking force as described above is to prevent the rotation of the platen roller 26. For this purpose, a braking force may be directly applied to the drive gear 31 connected to the platen roller 26. However, in this example, since the platen roller 26 and the drive gear 31 are attached to the slide frame 25 and move together with it, it is difficult to attach a mechanism for applying a braking force. Therefore, in this example, the rotation of the platen roller 26 is effectively prevented by applying a braking force to the gear 73 closest to the platen roller 26 among the gears attached to the frame 21. .
[0056]
(Another example of rotation restraint means)
In addition, it is also possible to attach a rotation prevention means instead of the rotation restraining means of this example. As the rotation preventing means, for example, a configuration in which the lock pin or the like is pressed against the third gear 73 in conjunction with the switching operation of the switching gear 62 to completely prevent the rotation of the gear can be employed. In this case, in conjunction with the stop of the drive motor 61, a lock pin or the like may be pressed against the third gear 73 to prevent the rotation of the gear.
[0057]
(Roll paper loading mechanism)
Next, the structure of the roll paper loading mechanism 2 in this example will be described in detail.
[0058]
6 is a perspective view showing a part of the roll paper loading mechanism 2 taken out, FIGS. 7 to 10 are explanatory views showing the opening and closing operation of the roll paper loading unit, and FIG. 11 is an explanation showing a partial configuration thereof. FIG.
[0059]
Referring to these drawings, the roll paper loading mechanism 2 has a mounting frame 21 attached to the printer main body frame 12. The roll paper loading mechanism 21 is loaded with the roll paper 4. Part 22 is configured. The roll paper loading unit 22 includes a semicircular curved portion 22a having a certain width and a rectangular opening 22b formed above, and the roll paper 4 is exchanged or replenished through the opening 22b.
[0060]
The roll paper loading opening 22 b can be opened and closed by a lid frame 23. The lid frame 23 includes a top plate portion 23a having a rectangular shape substantially the same as the opening 22b, and side plate portions 23b and 23c having a certain height and bent downward at right angles from the left and right of the top plate portion 23a. The rear end portions of the side plate portions 23b and 23c are bent downward, and the lower ends 23d and 23e (only the lower end 23d is shown in the figure) are rotatably supported by a shaft 24 that defines the turning center. Yes. Both ends of the shaft 24 are supported by the mounting frame 21. Accordingly, the lid frame 23 has the shaft 24 as the center, the closed position (the state shown in FIG. 7) where the roll paper loading opening 22b of the roll paper loading unit 22 is closed, and the open position where the opening 22b is fully opened. (The state shown in FIG. 10) can be turned.
[0061]
A slide frame 25 is attached to the lid frame 23 having this configuration. The slide frame 25 pivots integrally with the lid frame 23 and is slidable with respect to the lid frame 23, and has a platen roller 26 and a roll paper 4 on the platen roller 26 at the tip. Is attached. Thus, in this example, the lid frame 23 and the slide frame 25 constitute an open / close lid of the roll paper loading unit 22.
[0062]
First, a configuration in which the slide frame 25 is slidably attached to the lid frame 23 will be described with reference to FIG. The slide frame 25 includes a rectangular top plate portion 25a that is in contact with the back side of the top plate portion 23a of the lid frame 23, and a side plate that is bent downward at a right angle from both sides of the top plate portion 25a. And portions 25b and 25c. Guide slits 25d and 25f are formed in the top plate portion 25a in the front-rear direction, and guide pins 23q and 23r fixed to the surface plate portion 23a of the lid frame 23 pass through these slits. . Retaining rings 23h and 23i are attached to the lower ends of the guide pins 23q and 23r, whereby the slide frame 25 is slidably attached to the back surface of the lid frame 23.
[0063]
A coil spring 23g is bridged between a guide pin 23r on the rear side and a spring hook 25g formed on the front side portion of the slide frame 25, and the slide force is generated by the spring force of the coil spring 23q. The frame 25 is always biased rearward.
[0064]
Next, as can be seen from FIG. 6, a platen roller 26 is bridged between the front ends 25h, 25i of the side plate portions 25b, 25c of the slide frame 25, and both end portions of the support shaft of the platen roller 26 are at the front end. It is rotatably supported by 25h and 25i. A paper guide 27 having a convex arcuate surface shape is attached to the lower side of the platen roller 26 from the outer peripheral surface of the platen roller 26 toward the tangential direction.
[0065]
Here, when the platen roller 26 supported at the tip of the slide frame 25 is set to the operating position, the pressing roller 16 attached to the printer main body side on the outer peripheral surface of the platen roller 26 has a certain elasticity. A pressed state is formed with force. That is, the pressing roller 16 is slightly movable in the direction in which the rotation center shaft 16a approaches and separates from the platen roller 26, and is always urged toward the platen roller 26 by a spring force. Therefore, when the platen roller 26 is positioned at its operating position against the spring force, the outer peripheral surface of the platen roller 26 is pressed by the pressing roller 16 with the roll paper 4 sandwiched by a certain spring force. Become. As a result, when the platen roller 26 is rotationally driven, the roll paper 4 sandwiched between these rollers can be conveyed.
[0066]
Similarly, the surface 27a of the paper guide 27 attached to the tip of the slide frame 25 together with the platen roller 26 also applies the elastic force to the pressing roller 15 attached to the printer main body when the platen roller 26 reaches the operating position. Move against. As a result, the surface 27a of the paper guide 27 is also pressed by the pressing roller 15 with a certain elastic force with the roll paper 4 interposed therebetween.
[0067]
Next, a cover frame 28 having a size slightly larger is disposed on the upper side of the lid frame 23. The cover frame 28 includes a top plate portion 28a and side plate portions 28b and 28c bent at right angles downward from both sides thereof, and rear end portions of the side plate portions 28b and 28c extend downward. The shaft 24 is rotatably supported. When the cover frame 28 is turned, the lid frame 23 to which the slide frame 25 is attached is turned in conjunction with the cover frame 28. Further, after the lid frame 23 reaches the state (the state shown in FIG. 8) where the opening 22b for loading the roll is sealed, the cover frame 28 can be turned independently. The slide frame 25 slides in the front-rear direction with respect to the lid frame 23 by the single turning motion of the cover frame 28.
[0068]
The link mechanism 29 for converting the single pivot motion of the cover frame 28 into the slide motion of the slide frame 25 includes a connection shaft 28d spanned between the rear upper end portions of the side plate portions 28b and 28c of the cover frame 28, and the connection shaft. There are provided connection holes 25j formed in three places at the rear end portion of the slide frame 25 through which 28d passes. The connection hole 25j has a long and long hole shape so as not to hinder the single turning movement of the cover frame 28. Accordingly, the position of the connecting shaft 28d in the state where the cover frame 23 seals the opening 22b for loading the roll paper as shown in FIG. 8 further turns the cover frame 28 to the horizontal state as shown in FIG. In this case, the position is moved forward and downward about the shaft 24 that defines the turning center.
[0069]
The connecting shaft 28d freely moves downward along the vertically long connecting hole 25j and moves the connecting hole 25j by pushing it forward. As a result, the slide frame 25 in which the connection hole 25j is formed is pushed forward as a whole. That is, it slides forward with respect to the lid frame 23, the platen roller 26 and the paper guide 27 supported at the front end thereof protrude forward, and appear at the printing position 11 by the ink jet head 8, with respect to the ink jet head 8. It will be in the state (operating position) facing each other while maintaining a certain gap.
[0070]
Conversely, when the cover frame 28 is pivoted upward from the horizontal position shown in FIG. 7 to the position shown in FIG. 8, the slide frame 25 slides rearward as a whole, and the platen roller 26 at the tip thereof is reversed. The paper guide 27 moves from the operating position to the retracted position.
[0071]
Here, as described above, the slide frame 25 is urged by the coil spring 23g by an elastic force in the backward direction. Therefore, when the pressing force of the cover frame 28 is released after the cover frame 28 is closed to become horizontal as shown in FIG. 7, the slide frame 25 returns to its retracted position by the pulling force of the coil spring 23g. In conjunction with this sliding movement, the cover frame 28 also pivots in the opening direction and returns to the state shown in FIG.
[0072]
In order to lock the cover frame 28 in the closed position shown in FIG. 7, a pair of left and right engaging claws 28 g and 28 h are attached to the front end portion of the cover frame 28. When the cover frame 28 is closed, the hooks formed at the tips of the engaging claws 28g and 28h face the front portion of the mounting frame 21 where the hook pivots from below to be engaged. An engaging portion 21g is formed. The engaging claws 28g and 28h are always urged toward the direction in which the hook pivots upward by a torsion spring (not shown).
[0073]
Therefore, when the cover frame 28 is closed as shown in FIG. 7 and further pushed in, the engaging claws 28g and 28h slightly turn to the opposite side against the spring force, and the hooks at the lower ends thereof are lowered. Is engaged with the engaged portion 21g on the mounting frame 21 side to form a locked state. In order to release the lock, the upper end portions 28i of the engaging claws 28g and 28h may be pulled up and the lower end hooks may be turned downward.
[0074]
Next, in the roll paper loading mechanism 2 of this example, a mechanism for accurately positioning the position (operating position) of the platen roller 25 at the tip of the slide frame 25 with the cover frame 28 closed as described above. Is equipped. That is, positioning pins 25k and 25l for position definition (only the pin 25k is shown in FIG. 6) protruding horizontally to the left and right are attached to the front end portions of the side plate portions 25b and 25c of the slide frame 25. Yes. On the other hand, in a state where the slide frame 25 is closed, a semicircular shape in which the positioning pins 25k and 25l are fitted just in the lateral direction in the portion of the mounting frame 21 facing the positioning pins 25k and 25l. Grooves 21k and 21l are formed.
[0075]
Since these grooves 21k and 21l are formed at fixed positions, the positioning pins 25k and 25l of the slide frame 25 fit into these grooves 21k and 21l, so that the position of the platen roller 26 at the tip of the slide frame 25 is reached. (Operating position) is always accurately defined. Therefore, the platen roller 26 is always constant between the ink nozzle surface of the inkjet head 8 that reciprocates left and right with a predetermined gap with respect to the printing surface 11 on which the outer peripheral surface of the platen roller 25 is located. A gap is formed.
[0076]
In addition, coil springs 23j and 23k (between both side walls 21b and 21c of FIG. 6 (only 21b is shown in FIG. 6)) and side plate portions 23b and 23c on both sides of the lid frame 23 are respectively provided. In the figure, only the spring 23j is shown). When the cover frame 28, the slide frame 25, and the lid frame 23 are opened and closed with the shaft 24 as the center, after the center of gravity passes through the swiveling position shown in FIG. These coil springs 23j and 23k are arranged so that the turning trajectory of the spring hooking portions at both ends of 23j and 23k is widened.
[0077]
Accordingly, when the cover frame 28 is further opened beyond the swivel position shown in FIG. 9, the coil springs 23j and 23k are extended, so that a pulling force that biases the cover frame 28 in the closing direction acts. As a result, it is possible to avoid the adverse effect that the cover frame 28 and the like open vigorously and collide with other parts.
[0078]
Conversely, even when the cover frame 28 is closed beyond the swivel position shown in FIG. 9, the cover frame 28 closes vigorously by the spring force of these coil springs 23j, 23k, and opens into the opening 22b of the roll paper loading unit. The adverse effect of colliding can be avoided.
[0079]
(Operation of roll paper loading mechanism)
The opening / closing operation of the roll paper loading unit 22 in the roll paper loading mechanism 2 will be described collectively with reference to FIGS. First, when the upper end portion 28i connected to the engaging claws 28g and 28h is pulled upward in the state where the roll paper loading unit 22 is closed as shown in FIG. 7, the engaging claws 28g and 28h are moved to the frame 21 side. Is disengaged from the engaged portion 21g and the lock is released. As a result, the cover frame 28, the slide frame 25, and the lid frame 23 are integrally turned to the position shown in FIG. This turning operation is performed mainly by the spring force of the coil spring 23g that spans between the slide frame 25 and the lid frame 23.
[0080]
Thereafter, when the cover frame 28 is rotated backward against the spring force of the coil springs 23j, 23k, the opening 22b of the roll paper loading unit 22 is opened as shown in FIG. Fully open. That is, all of the cover frame 28, the slide frame 25, and the lid frame 23 are retracted from above the opening 22b.
[0081]
After the fully opened state, the roll paper 4 loaded in the roll paper loading unit 22a is exchanged. Since the opening 22b is in a fully open state, the replacement work of the roll paper 4 is simple. Further, since the platen roller 26 and the paper guide 27 are also retracted together with the slide frame 25, the work of arranging the unwinding portion 4a of the roll paper 4 can be easily performed.
[0082]
After the roll paper 4 is loaded, the cover frame 28 is turned in the closing direction. By this operation, the cover frame 28, the slide frame 25, and the lid frame 23 rotate together, and after the state shown in FIG. 9, the lid frame 23 seals the opening 22b as shown in FIG. . After this, the lid frame 23 engages with the edge of the opening 22b and does not turn any further. Therefore, the slide frame 25 slidably attached to the lid frame 23 does not turn any further. Therefore, after this, only the cover frame 28 turns alone. When the cover frame 28 is pushed and swung to the position shown in FIG. 7, this swiveling motion is converted into a slide motion of the slide frame 25 via the link mechanism 29. That is, the slide frame 25 slides forward with respect to the lid frame 23, and the platen roller 26 and the paper guide 27 supported at the front end of the slide frame 25 face each other with a fixed gap (operation). Position). When the slide frame 25 slides forward, the positioning pins 25k and 25l at both ends of the slide frame 25 fit into the grooves 21k and 21l on the mounting frame 21 side, and the slide position is fixed. In other words, the platen roller 26 and the paper guide 27 are held at a preset facing position, and a certain gap is formed between the platen roller 26 and the paper guide 27.
[0083]
In this state, the driven gear 31 connected to one end of the platen roller 26 is engaged with a driving gear (not shown) arranged on the mounting frame 21 side. Accordingly, when the drive side gear rotates, the platen roller 26 rotates, and the unwinding portion 4a of the roll paper 4 is conveyed in the conveyance direction (arrow direction), and is predetermined by the inkjet head 8 in synchronization with this conveyance operation. The printing operation is performed.
[0084]
(Other embodiments)
The above description relates to an embodiment in which the present invention is applied to an inkjet printer. The present invention can be similarly applied to a print head other than an ink jet head as a print head, for example, a printer provided with a wire dot head.
[0085]
In addition, the ink jet printer described above is configured to perform printing on cut paper as well as roll paper. However, a printer mounted on a POS terminal or the like that performs printing only on roll paper that is generally used. Of course, the present invention can be similarly applied to the above.
[0086]
【The invention's effect】
As described above, the printer of the present invention includes the rotation restraining means or the rotation preventing means, and the rotation of the roller is not transmitted to the roll paper feed roller for conveying the roll paper. Can be prevented. Therefore, it is possible to prevent the roll paper feed roller from rotating and the roll paper stretched around the roll paper from loosening and floating from the roller to bend toward the print head. As a result, it is possible to prevent problems such as the roll paper coming into contact with the print head and causing ink stains due to the roll paper rising, or jamming of the roll paper at the print head portion.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an ink jet printer to which the present invention is applied.
FIG. 2 is an explanatory diagram showing a paper conveyance path in the ink jet printer of FIG. 1;
3 is a configuration diagram showing a configuration of tension applying means for applying a tensile force to the roll paper in the ink jet printer of FIG. 1. FIG.
4 is a schematic configuration diagram showing a driving force transmission mechanism in the ink jet printer of FIG. 1. FIG.
5A is a schematic configuration diagram showing a driving force transmission mechanism in the ink jet printer of FIG. 1, and FIG. 5B is a schematic configuration diagram showing a configuration of rotation restraining means.
6 is a partial perspective view showing a roll paper loading mechanism extracted from the ink jet printer of FIG. 1; FIG.
7 is an explanatory diagram illustrating a state in which a roll paper loading unit of the roll paper loading mechanism in FIG. 6 is closed.
FIG. 8 is an explanatory diagram showing a state after the lock of the cover frame that closes the roll paper loading unit of the roll paper loading mechanism of FIG. 6 is released.
9 is an explanatory view showing a state in which the cover frame of the roll paper loading mechanism of FIG. 6 is opened until it is almost vertical.
10 is an explanatory diagram showing a state in which a roll paper loading unit of the roll paper loading mechanism of FIG. 6 is fully opened.
11 is an explanatory diagram showing a state in which the slide frame is attached to the lid frame in the roll paper loading mechanism of FIG.
[Explanation of symbols]
1 Inkjet printer
2 Roll paper loading mechanism
3 Cut paper slot
4 roll paper
4a Roll paper unwinding part
4A roll body
4B Roll paper printing surface
5 sheet paper
6 Guide shaft
7 Carriage
8 Inkjet head
10 Ink supply section
11 Print position
12 Printer body frame
13, 14 Roll support rollers
15 Pressing roller (pressing member)
15a Rotation center axis
15b Roller body
15c Spring member
16 Pressing roller
16a Rotation center axis
16b Roller body
16c Spring member
21 Mounting frame
22 Roll paper loading section
22b Opening of roll paper loading unit
23 Lid frame
24 Shaft that defines the center of rotation
25 Slide frame
25j connecting hole
26 Platen roll
27 Paper guidance
27a Paper guide surface
28 Cover frame
28d connecting shaft
29 Link mechanism
31 Drive gear
51, 53, 55 Paper feed roller
61 Drive motor
62 Switching gear
71-73 Gears constituting roll paper transport gear train
81-87 Gears constituting a cut sheet transporting gear train
88, 89, 90 Drive gear
92 Brake plate
93 lever
94 Supporting point member
95 Coil spring

Claims (9)

A drive motor;
A roll paper feed roller;
A single sheet paper feed roller,
A roll paper transport gear train for transmitting the rotation of the drive motor to the roll paper feed roller;
A cut paper transporting gear train for transmitting rotation of the drive motor to the cut paper feed roller;
A switching gear capable of moving between a roll paper drive position capable of transmitting the rotation of the drive motor to the roll paper transport gear train and a cut paper drive position capable of being transmitted to the cut paper feed roller; Switching means,
Rotation restraining means for applying a braking force for restraining free rotation to the gear included in the roll paper transport gear train;
Tension applying means capable of applying a tensile force toward the conveyance direction on the print surface portion of the roll paper conveyed via the print position by the print head,
Even when the switching gear is in the cut sheet drive position, the rotation of the roll paper feed roller is restricted by the rotation restricting means, and the tension applied to the print surface portion of the roll paper by the tension applying means. A printer characterized in that force is retained. In claim 1,
A roll paper loading unit for loading roll paper and an opening / closing lid for opening / closing the roll paper loading unit, and the roll paper feed roller moves to an operating position and a retracted position in conjunction with opening / closing of the opening / closing lid. And
The tension applying means applies a tensile force to the print surface portion of the roll paper when the roll paper feed roller is in the operating position, and the tensile force when the roll paper feed roller is in the retracted position. A printer characterized by canceling. In claim 2,
The roll paper feed roller is attached to the opening / closing lid, and when the opening / closing lid is closed, the operation position is reached.
A paper guide for guiding the roll paper toward the roll paper feed roller is attached to the opening / closing lid,
The printer, wherein the print surface portion of the roll paper is bridged between the paper guide and the roll paper feed roller in a state where the open / close lid is closed. In claim 2 or 3,
The roll paper transport gear train includes a gear that rotates integrally with the roll paper feed roller, and a braking force is applied to the gear that is directly meshed with the gear by the rotation restraining means. Printer. A drive motor;
A roll paper feed roller;
A single sheet paper feed roller,
A roll paper transport gear train for transmitting the rotation of the drive motor to the roll paper feed roller;
A cut paper transporting gear train for transmitting rotation of the drive motor to the cut paper feed roller;
A switching gear capable of moving between a roll paper drive position capable of transmitting the rotation of the drive motor to the roll paper transport gear train and a cut paper drive position capable of being transmitted to the cut paper feed roller; Switching means,
Rotation preventing means capable of preventing rotation of gears included in the roll paper transport gear train, wherein the roll paper transport is performed while the rotation of the drive motor is transmitted to the cut paper transport gear train. Preventing rotation of gears included in the gear train,
Tension applying means capable of applying a tensile force toward the conveyance direction on the print surface portion of the roll paper conveyed via the print position by the print head,
Even when the switching gear is at the cut sheet drive position, the rotation prevention unit prevents the roll paper feed roller from rotating, and the tension application unit applies the tension applied to the print surface portion of the roll paper. A printer characterized in that force is retained. In claim 5,
A roll paper loading unit for loading roll paper and an opening / closing lid for opening / closing the roll paper loading unit, and the roll paper feed roller moves to an operating position and a retracted position in conjunction with opening / closing of the opening / closing lid. And
The tension applying means applies a tensile force to the print surface portion of the roll paper when the roll paper feed roller is in the operating position, and the tensile force when the roll paper feed roller is in the retracted position. A printer characterized by canceling. In claim 6,
The roll paper feed roller is attached to the opening / closing lid, and when the opening / closing lid is closed, the operation position is reached.
A paper guide for guiding the roll paper toward the roll paper feed roller is attached to the opening / closing lid,
The printer, wherein the print surface portion of the roll paper is bridged between the paper guide and the roll paper feed roller in a state where the open / close lid is closed. In claim 6 or 7,
The roll paper transport gear train includes a gear that rotates integrally with the roll paper feed roller, and the gear that is directly meshed with the gear is prevented from rotating by the rotation preventing means. In any one of claims 1 to 8,
A printer comprising an ink jet head or a wire dot head as a print head.

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