JP2013103482A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printer capable of properly adjusting a contact pressure in a pressing point between a platen roller and a print head.SOLUTION: The printer 1 includes a lug 4a of a support plate 4 for supporting a print head 3 pressed against the platen roller 2, and a guide 5a engaged with the lug 4a, wherein the lug 4a has an abutment 4ac abutted against the guide 5a at a contact point P located at the side of the platen roller 2 with respect to the tangent in the pressing point where the platen roller 2 is pressed against the print head 3.

Description

  The present invention relates to a printer that feeds a belt-shaped print medium and prints on the print medium, and relates to a support plate that supports a print head used in the printer and a guide unit.

  As a printer for feeding a printing medium and printing on a printing medium, there is a printer described in Patent Document 1, for example. In such a printer, various types of information are printed on a print medium.

  In the printer described in Patent Document 1, the platen roller that constitutes the printing unit and the platen roller that is one of the print heads are connected to the movable unit that is an open / close cover that is connected to the main body frame that is a fixed unit via a hinge. A support plate that is disposed and supports the other print head is disposed in the fixed portion.

  When placing the support plate on the fixed portion, the support plate is formed in a rectangular shape that is elongated in the axial direction of the platen roller, and is provided with positioning ears at both ends, and the guide corresponding to the ear portion is provided on the fixed portion. A part is provided and an ear part is engaged with a guide part. With such a configuration, the platen roller is rotated so that the print medium is sandwiched between the platen roller and the print head, printing is executed, and the print medium after printing is sent out from the printer.

  In such a printer, when the platen roller is rotated as described above while pressing the platen roller, the support plate is rotated at the pressing point between the platen roller and the printing medium by the rotation accompanied by the pressing of the platen roller. The support plate, and thus the print head is positioned by moving in the direction of the tangent line and bringing the ear portion into contact with the guide portion.

JP 2002-120389 A

  However, in the above-described prior art, the contact point of the ear portion with the guide portion is located on the outer side in the radial direction of the platen roller with respect to the tangent line to which the printing medium is sent from the pressing point of the platen roller with the print head. As a result, a moment in the direction approaching the platen roller acts on the support plate, causing a problem that the contact pressure at the pressing point becomes excessive.

  In view of the above problems, an object of the present invention is to provide a printer that can make an appropriate contact pressure at a pressing point between a platen roller and a print head.

In order to solve the above problem, a printer according to the present invention provides:
An ear portion of a support plate for supporting the print head pressed against the platen roller;
A guide part to which the ear part is engaged,
The ear portion has a contact portion that contacts the guide portion at a contact point located on the platen roller side with respect to a tangent at a pressing point where the platen roller is pressed against the print head. .

Here, in the printer,
The ears protrude from the support plate on both sides in the axial direction of the platen roller, and
An extension part extending toward the platen roller side from the axial end of the protrusion part, and the contact part may be provided on the platen roller side of the extension part. The contact portion may have an arc shape when viewed from the axial direction of the platen roller. In addition, it is preferable that the part which the said contact part and the said guide part contact mutually is made of a material with a low friction coefficient.

  According to the printer of the present invention, even if the support plate is moved in the tangential direction due to the rotation of the platen roller against the print head, the ear portion becomes the guide portion at the contact point located on the platen roller side. Therefore, the contact pressure can be effectively prevented from being excessively increased by setting the moment acting on the support plate as the direction in which the support plate is separated from the platen roller.

1 is a schematic perspective view mainly showing a portion related to the present invention in an embodiment of a printer 1 of an example according to the present invention. 1 is a schematic perspective view showing a structure which is a premise of an embodiment of a printer 1 of an example according to the present invention. 3 is a schematic diagram showing an aspect of a moment M1 acting on the support plate 14 in the premise structure of the embodiment of the printer 1 of the embodiment according to the present invention when viewed from the axial direction of the platen roller 2. FIG. FIG. 3 is a schematic diagram showing an aspect of a moment M2 acting on the support plate 4 in the embodiment of the printer 1 of the embodiment according to the present invention when viewed from the axial direction of the platen roller 2;

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.

  As shown in FIG. 1, the printer 1 of this embodiment has ears 4a protruding from both sides of the support plate 4 that supports the print head 3 pressed by the platen roller 2, and the ears 4a have appropriate play. The ear 4a is guided at a contact point P located on the platen roller 2 side with respect to a tangent at a pressing point at which the platen roller 2 is pressed against the print head 3. It has the contact part 4ac contact | abutted to the part 5a.

  1 is a straight line extending in the lateral direction in which the outer peripheral surface of the platen roller 2 and the surface on the front side of the print head 3 are in contact with each other via the print medium in FIG. 2 are rectangular vertical lines constituting the front side of the print head 3. Positioning on the platen roller 2 side with respect to the tangent is a positional relationship when viewed from the axial direction of the platen roller 2. In other words, the abutting portion 4ac only needs to be offset to the front side with respect to the front side surface of the print head 3. Further, appropriate play of the ear part 4a with respect to the guide part 5a is provided both in the tangential direction and in the radial direction of the platen roller 2.

  The print head 3 is composed of a rectangular thermal head made of ceramic, for example, and has a large number of dot-like heating elements arranged on the front surface in FIG. The print command is controlled to print on the print medium while the heating element is electrically scanned.

  The support plate 4 is formed by, for example, pressing a metal plate with high heat dissipation, and has a substantially rectangular shape whose vertical and horizontal dimensions are larger than the rectangular shape of the print head 3. The back surface of the print head 3 is joined by the joining means. The ears 4a are formed so as to protrude in the left-right direction in FIG. 1, that is, in the axial direction of the platen roller 2 from the portion located on the back side of the upper end of the print head 3 of the support plate 4.

  The ears 4a are a pair of projecting portions 4aa projecting from the support plate 4 to both sides in the axial direction of the platen roller 2, and the end portions of the projecting portions 4aa in the axial direction from the platen roller 2 side, that is, from the back of the support plate 4 to the front. The abutting portion 4ac is provided so as to protrude from the end of the extending portion 4ab on the platen roller 2 side in the upward direction in FIG. 1, that is, in the tangential direction.

  Here, the extending portion 4ab is perpendicular to the protruding portion 4aa, and the protruding portion 4aa and the extending portion 4ab are L-shaped when viewed from the upper direction in FIG. 1, that is, from the tangential direction. The boundary portion between the protruding portion 4aa and the extending portion 4ab is formed by bending by the above-described pressing.

  The extension part 4ab and the contact part 4ac are also L-shaped when the platen roller 2 is viewed in the axial direction. The contact part 4ac is formed by punching a plate-like member constituting the extension part 4ab by the above-described pressing. Further, the contact portion 4ac has an arc shape when viewed from the axial direction of the platen roller 2 in order to reduce friction caused by contact with the guide portion 5a.

  The printer 1 has a main body frame 5 having a substantially box shape as indicated by a broken line in FIG. 1, and the guide portions 5 a are platen plates provided on side walls located on both sides of the main body frame 5 in FIG. 1. It is constituted by a rectangular hole that is long in the direction approaching or separating from the roller 2.

  A pair of left and right springs 6 that urge the support plate 4 in the direction approaching the thermal head 2 are provided between the wall surface on the back side of the main body frame 5 and the support plate 4. The spring 6 may be a leaf spring or other elastic element.

  The main body frame 5 is provided with a paper insertion slot 5b on the lower end side of the wall surface on the front side in FIG. 1, and accommodates a paper roll located on the front side of the paper insertion slot 5b (not shown in FIG. 1). The print medium drawn out from the roll paper stored in the sheet is inserted from the paper insertion opening 5b to the back side, and is sandwiched between the print head 3 and the platen roller 2, and then is positioned on the upper side in FIG. Do not have a path sent out from the outlet.

  The platen roller 2 constitutes a transport unit that pulls out the print medium from the roll paper (not shown). A drive transmission gear (not shown) is provided on one end side of the platen roller 2.

  In the space behind the support plate 4 of the main body frame 5, a drive gear and a platen drive motor are arranged close to the transmission gear described above, and a driver board and a battery (not shown) are arranged in the vicinity thereof.

  The platen drive motor is driven by a battery based on a driver board control based on a paper feed command or a print command by manual or automatic control, and a drive gear, a transmission gear, and a platen roller 2 (not shown) are driven. The print medium is conveyed, and in the case of a print command, printing by the print head 3 is simultaneously performed on the print medium, and the print medium after printing is discharged upward from the above-described delivery port.

  Although not shown in the present embodiment, the main body frame 5 may be provided with an open / close cover that can be freely opened and closed with respect to the main body frame 5. In this case, the platen roller 2 and the transmission gear described above are A lock mechanism configured by, for example, a toggle mechanism, which is installed on the opening / closing cover side and locks the opening / closing cover with respect to the main body frame 5 when the opening / closing cover is in the closed position with respect to the main body frame 5 is appropriately provided.

  As described above, the printer 1 according to the present embodiment has a configuration in which the ear portions 14a located at both ends of the support plate 14 provided in the base structure shown in FIG. However, an extending portion 4ab that is directed to the front side of the print head 3 is provided to form an L shape, and the end portion of the extending portion 4ab projects beyond the front surface of the print head 3, and the extending portion is formed. The difference is that an abutting portion 4ac protruding from the end of 4ab in the direction of the tangent is provided. In addition, with this difference, the guide portion 5a included in the printer 1 of the present embodiment has a longer shape in the front-back direction of the support plate 4 than the guide portion 15a in the premise structure.

  The printer 1 according to the present embodiment has the above-described features, and thus can obtain advantageous effects as described below with respect to the premise structure. This function and effect will be described below with reference to FIG. 3 which is a cross-sectional view perpendicular to the axial direction of the platen roller 2 in FIG. 2 and including the guide portion 15a, and perpendicular to the axial direction of the platen roller 2 in FIG. This will be described with reference to FIG. 4 which is a sectional view including the guide portion 5a.

  That is, in the premise structure as shown in FIG. 2, as shown in FIG. 3, the outer peripheral surface A of the platen roller 2 is located on the spring 6 with respect to the rigid body B including both the ears 14 a and the print head 3. While being pressed by the urging force F1, a tangential force F2, which is a force in the tangential direction, is exerted by the clockwise rotation φ for conveying the print medium, so that the upper wall surface C on the upper side of the guide portion 15a of the rigid body B is applied. The contact point with respect to is D which is the end on the side away from the platen roller 2.

  When the rigid body B comes into contact with the upper wall surface C by the end point D and the urging force F1 is slid by a predetermined play amount in the direction in which the ear portion 14a is separated from the platen roller 2 in the guide portion 15a, the guide portion Since it abuts against the back wall surface on the back side of 15a and is canceled by the reaction force, and the tangential force F2 continues to act, a counterclockwise moment M1 indicated by a hollow arrow in FIG. 3 is generated.

  This moment M1 rotates the rigid body B counterclockwise, and exerts a pressing force that presses the print head 3 in a direction approaching the platen roller 2. If this pressing force is excessive, the durability of the print head 3 is increased. There is a risk of inconvenience such as lowering or causing an overcurrent or a step-out of the platen driving motor that drives the platen roller 2.

  On the other hand, in the printer 1 of this embodiment, as shown in FIG. 4, the outer peripheral surface A of the platen roller 2 is attached to the spring 6 with respect to the rigid body B including both the ears 4 a and the print head 3. While being pressed by the force F1, a tangential force F2, which is a force in the direction of the tangent L, is exerted by the clockwise rotation φ for conveying the print medium, but the upper wall surface C on the upper side of the guide portion 5a of the rigid body B. The contact point with respect to is a contact point P due to the contact portion 4ac located offset from the tangent line L by the length of the extended portion 4ab on the platen roller 2 side.

  The rigid body B comes into contact with the upper wall surface C by the contact point P, and the urging force F1 is guided when a predetermined play amount is slid in the direction in which the ear portion 4a is separated from the platen roller 2 in the guide portion 5a. Since it abuts against the back wall surface on the back side of the portion 5a and is canceled by the reaction force, and the tangential force F2 continues to act, a clockwise moment M2 indicated by a white arrow in FIG. 4 is generated.

  This moment M2 acts in a direction to rotate the rigid body B in the clockwise direction and move the print head 3 away from the platen roller 2, so that the pressing force pressing the print head 3 against the platen roller 2 is less than the urging force by the spring 6 only. It is possible to prevent the pressing force from becoming excessive. That is, it is possible to avoid the occurrence of inconveniences such as the durability of the print head 3 being lowered or the platen driving motor driving the platen roller 2 being overcurrent or out of step due to the excessive pressing force. be able to.

  Further, according to the printer 1 of the present embodiment, it is not necessary to configure the outer peripheral surface of the platen roller 2 with a special rubber having a low friction coefficient from the standpoint of preventing step-out in particular. Can be prevented. In addition, the transition operation from the stop of the printer 1 to the printing or paper discharge can be made smooth, and in particular, the automatic paper feeding operation after replacing the roll paper can be stably realized.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions are made to the above-described embodiments without departing from the scope of the present invention. be able to.

  For example, in the embodiment described above, the shape of the guide portion 5a is rectangular, but it may be fan-shaped with the lower side of the printer 1 as the center. Whether or not the lower end portion of the support plate 4 abuts on the main body frame 5 can be appropriately selected.

  In addition, the shearing surface by press working that forms the arc shape of the plate-shaped member constituting the contact portion 4ac and the upper wall surface of the guide portion 5a are both made of a material having a low friction coefficient in order to make the relative movement smoother. It is good also as what comprises. In this case, the material of the support plate 4 and the main body frame 5 itself may be selected as appropriate, or the appropriate surface may be coated or surface-treated with an appropriate material.

  Further, in the above-described embodiment, a mechanism for making the support plate 4 detachable with respect to the main body frame 5 is not particularly illustrated, but for example, at the upper part on the back side of the guide portion 5a, the ear portion 4a of the support plate 4 By providing a notch part into which can be inserted, it can be made removable as appropriate.

  The present invention relates to a mode of engagement or locking of a support plate of a print head of a printer to a main body frame, and the support plate moves in a tangential direction by rotation accompanied by pressing of a platen roller to the print head. In this case, since the ears located on both sides of the support plate are brought into contact with the guide portion at the contact point located on the platen roller side with respect to the tangent line, the moment acting on the support plate is always separated from the platen roller. Direction.

  In the present invention, by controlling the direction of the moment, it is avoided in advance that the support plate and thus the print head is excessively pressed against the platen roller, and the contact pressure at the pressing point of the platen roller to the print head is excessive. It can be effectively prevented. Therefore, the present invention is useful when applied to various types of printers having a print head and a support plate.

DESCRIPTION OF SYMBOLS 1 Printer 2 Platen roller 3 Print head 4 Support plate 4a Ear | edge part 4aa Projection part 4ab Extension part 4ac Contact part 5a Guide part 5b Paper insertion slot 5 Main body frame (housing)
6 Spring

Claims (3)

  An ear portion of a support plate that supports the print head pressed against the platen roller; and a guide portion with which the ear portion is engaged. The ear portion is a pressure that presses the platen roller against the print head. A printer having a contact portion that contacts the guide portion at a contact point located on the platen roller side with respect to a tangent at the point.   The ear portion includes a protruding portion that protrudes from the support plate on both sides in the axial direction of the platen roller, and an extending portion that extends from the axial end portion of the protruding portion toward the platen roller, The printer according to claim 1, wherein the contact portion is provided on the platen roller side of the extension portion.   The printer according to claim 2, wherein the contact portion has an arc shape when viewed from the axial direction of the platen roller.

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