JPH05212923A - Thermal recorder - Google Patents

Abstract

PURPOSE:To obtain a thermal recorder which is simplified in structure, reduced in number of component parts, improved in accuracy, and facilitated in maintenance. CONSTITUTION:A thermal recorder is provided with a chassis 1 having support walls 2, 2 integrally erected from the both side edges thereof; a head mounting plate 16 supporting a thermal head 18 rotatably on the chassis 1; bearing cutouts 3 formed on the support walls for supporting a platen roller shaft 11 with an allowance and provided with positioning parts 3a for positioning the shaft 11; and pressing springs 21, 21 pressing the thermal head against a platen roller and abutting the platen roller shaft on the positioning parts.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel thermal recording apparatus. More specifically, it is an object of the present invention to provide a novel thermal recording apparatus having a simple structure, a small number of parts, high accuracy, and easy maintenance.

[0002]

2. Description of the Related Art A conventional thermal recording apparatus used in a facsimile machine, a copying machine or the like has a structure as shown below because it is necessary to separate a platen roller from a thermal head when replacing a sheet (FIG. 9). reference).

Reference numeral a is an arm supported by a chassis or a casing, which is provided on each side. A cover (not shown) that opens and closes the mounting portion of the thermal recording paper is supported by the arm a, and a shaft c of the platen roller b is rotatably supported at a position near the rotating end of the arm a.

D is a thermal head arranged in the housing,
Reference numeral e denotes a receiving member that receives the shaft c of the platen roller b, and a notch f is formed in the receiving member e. By receiving the shaft c in the notch f, a direction in which the shaft c exists (the notch f Positioning is performed in the width direction. Then, such receiving members e are provided on both sides.

Reference numeral g denotes a lock member rotatably provided on the housing or chassis, and the lock claw h is provided at a position near the rotation end.
have. Such lock members g are also provided on both sides. Then, when the lid is closed and the platen roller b is pressed against the thermal head d, the lock claw h of the lock member g is engaged with the locked pin i provided on the arm a to fix the position of the arm a.

In such a heat-sensitive recording apparatus, elastic means (not shown) is provided so that the platen roller b is pressed against the thermal head d with a predetermined elastic force. ..

[0007]

In the above-described conventional thermal recording apparatus, the two lock members g, in which the arms a, which are members supporting the platen roller b, are separate left and right, and separate left and right. Since it is locked by, the accuracy is difficult to obtain, and in many cases there is a problem that the lock is dominated. If the lock is unilateral, the pressure contact state between the platen roller b and the thermal head d will not be uniform over the entire length of the thermal head d, and the print quality will be uneven in the longitudinal direction of the thermal head d. There is a problem of becoming.

Further, in order to lock the arm a, the arm a is once moved further to the thermal head d side than the position where the lock claw h of the lock member g and the locked pin i are engaged, that is, There is a problem in that operability is poor because an overstroke is required and the lid must be closed against the strong elastic force of the elastic generating means.

[0009]

In order to solve the above-mentioned problems, the thermal recording apparatus of the present invention rotates a thermal head with respect to a chassis having an integral support wall erected from both side edges. A head mounting plate that freely supports, a bearing notch that is formed on the support wall and that supports the shaft of the platen roller with a margin and that has a positioning portion that positions the shaft, and the thermal head to the platen roller. And a pressing spring that presses the shaft of the platen roller against the positioning portion.

[0010]

Therefore, in the heat-sensitive recording apparatus of the present invention, the shaft of the platen roller is brought into contact with the positioning portion of the bearing notch formed in the support wall integrally provided upright on both side edges of the chassis for positioning. Therefore, the positioning accuracy is easily obtained, and the contact state between the platen roller and the thermal head does not become non-uniform in the axial direction.

Moreover, the above-mentioned accuracy can be obtained and the structure is simplified by using a smaller number of parts than the conventional one.

[0012]

The details of the thermal recording apparatus of the present invention will be described below with reference to the embodiments shown in the accompanying drawings.

Reference numeral 1 is a chassis formed by bending a sheet metal material, and support walls 2 and 2 are integrally provided upright from both side edges.

The support walls 2 and 2 are formed with bearing notches 3 and 3 which are open at their upper edges. The bearing notch 3 has a substantially rectangular shape, and the front edge 3a serves as a positioning portion. Further, the upper end portion 3b of the front edge 3a is inclined so as to fall backward.

An inlet / outlet portion 4 is continuously provided at the upper end of the bearing notch 3, and a front edge of the inlet / outlet portion 4, that is, a portion 4a continuous with the upper end 3b of the front edge of the bearing notch 3 goes to the front side as it goes upward. It is an introduction part that is inclined so as to be displaced.

Denoted at 5 and 5 are trapezoidal stoppers provided at positions near the upper ends of the rear edges of the support walls 2 and 2.

Reference numerals 6 and 6 denote attachment pieces protruding toward the rear end portions of the upper edges of the support walls 2 and 2 so that the attachment pieces 7 project outwardly at the front end portions of the upper edges of one of the support walls 2. It is a mounting piece provided in.

Reference numeral 8 denotes a connecting member, both ends of which are screwed to the mounting pieces 6, 6 of the supporting walls 2, 2 so that the upper ends of the supporting walls 2, 2 are connected.

Reference numerals 9 and 9 denote arms, the front ends of which are rotatably supported at a position in front of the support walls 2 and 2 of the chassis 1, and which are provided on the front of a casing (not shown) for replacing sheets. A lid (not shown) that opens and closes the opening is attached.

Reference numeral 10 is a platen roller, and 11 is a platen roller 10 which penetrates the platen roller 10 and has both ends thereof.
It is a platen shaft protruding from both ends of 0. 12, 12
Is a cylindrical bearing member that is externally fitted and fixed to a portion of the platen shaft 11 that protrudes from the platen roller 10, and has flanges 12a and 12a formed at its outer ends.

Reference numerals 13 and 13 are also cylindrical bearing members, which are externally fitted and fixed to portions of the platen shaft 11 projecting from the bearing members 12 and 12. In addition, these bearing members 12,
12, 13, 13 are formed of a synthetic resin material having good slipperiness, for example, Delrin (trade name of DuPont, USA).

A platen gear 14 is fixed to one end of the platen shaft 11.

A bearing member 1 externally fitted to a platen shaft 11 of a platen roller 10 is provided at the rotating end of the arms 9 and 9.
Support holes 15 having a diameter slightly larger than the outer diameters of 2 and 12
5 is formed and the flanges 1 of the bearing members 12, 12 are formed.
2a, 12a is the support hole 1 for the arm 9, 9
5 and 15 are supported with a margin.

However, when the arms 9 and 9 are rotated upward, the platen shaft 11 of the platen roller 10 is in a state of protruding upward from the bearing notches 3 and 3 of the chassis 1, and this state is the sheet exchange. It is in the released state.

When the arms 9, 9 are rotated downward from the released state, the bearing members 13, 13 firstly move the support walls 2,
The bearing members 13, 13 move downward while rolling on the inlets 4a, 4a as they come into contact with the inlets 4a, 4a of the inlet / outlet 4 and the arms 9, 9 further rotate downward. I will do it. And finally, the bearing members 13, 13
Are located in the bearing notches 3,3. Then, in this state, the support holes 15, 15 of the arms 9, 9 and the bearing members 12, 12
The bearing members 13 and 13 are in a state capable of being slightly moved in the bearing notches 3 and 3 due to the difference in shape between and (see FIG. 7).

Reference numerals 16 and 16 are head mounting plates for supporting a thermal head described later.

The head mounting plates 16 and 16 have a vertically long plate shape, and the lower ends thereof are rotatably supported at positions near the rear ends of the lower ends of the support walls 2 and 2. In addition, support pieces 17 and 17 protruding toward each other are bent and formed on the upper half portions of the rear edges of the head mounting plates 16 and 16.

Notches are formed at the upper ends of the front edges of the head mounting plates 16 and 16, and lower edges 16a and 16a of the notches are positioning edges that extend substantially horizontally.

Reference numeral 18 denotes a thermal head, which supports a heating element 20 in which heating elements are arranged in a line on the front surface of a head substrate 19 having a plate shape elongated in the left-right direction, and both ends of the head substrate 19 are supported. Are fixed to the supporting pieces 17, 17 of the head mounting plates 16, 16, whereby the thermal head 18 is rotatably supported by the supporting walls 2, 2 of the chassis 2 via the head mounting plates 16, 16. To be done.

Reference numerals 21 and 21 denote head pressing springs made of a leaf spring material, the lower end of which is fixed to the bottom plate 1a of the chassis 1 and the upper end of which is elastically contacted with the rear surface of the head substrate 19. The moving force of the thermal head 18 in the substantially forward direction is elastically biased. The forward movement range of the thermal head 18 is regulated when the support pieces 17, 17 of the head mounting plates 16, 16 come into contact with the rear ends of the stoppers 5, 5 of the support walls 2, 2 to prevent the thermal head 18 from moving. It is designed not to move forward any more than necessary.

The heating element 20 of the thermal head 18 is elastically contacted with the platen roller 10 while the platen roller 10 is supported by the bearing notches 3 and 3 of the support walls 2 and 2 as described above.

Further, at this time, the head mounting plates 16, 16
The positioning edges 16a, 16a are located slightly above the lower edges of the bearing notches 3, 3 of the support walls 2, 2, and the platen roller 10 has its shaft 11 (bearing members 13, 13) at the bearing notches 3, 3, 3. The front edge 3a, 3a and the positioning edges 16a, 16a of the head mounting plates 16, 16 are brought into contact and positioned (see FIG. 8).

Reference numeral 22 denotes a release lever for separating the thermal head 18 from the platen roller 10 when the platen roller 10 is moved together with a lid (not shown) at the time of replacing a sheet.

The release lever 22 has a plate-like shape that is long in the front-rear direction, and its front end is rotatably supported at a position near the lower end of the front end of the other support wall 2. Further, the handle portion 23 is formed by bending outward at the rotating end portion.

Reference numeral 24 denotes a rotation fulcrum portion 22a of the release lever 22.
Is a pressing piece that is bent and formed so as to project outward in the vicinity of. Then, the pressing piece 24 is positioned in contact with or close to the front edge of the other head mounting plate 16 in the substantially middle portion in the vertical direction from the front.

When the handle portion 23 is pressed downward, the release lever 22 rotates, and the pressing piece 24 of the head mounting plate 16 moves the portion above the rotation fulcrum of the front edge of the head mounting plate 16 rearward. Since the head mounting plates 16 and 16 and the thermal head 18 rotate backward, the thermal head 18 is pressed.
Separates from the platen roller 10 rearward.

Reference numeral 25 denotes a motor mounting plate having a rectangular shape which is long in the front-rear direction. The mounting plate 26 is provided so as to project inward from a position near the front end of the upper edge and a position slightly rearward from the center of the lower edge. A mounting piece 27 projecting from is bent and formed.

Reference numeral 28 denotes a motor fixed outside the position near the front end of the motor mounting plate 25, and a pinion 29 is fixed to a rotary shaft 28a of the motor 28 protruding inward from the motor mounting plate 25. ..

An intermediate gear 30 is rotatably supported inside a substantially central portion of the motor mounting plate 25 in the front-rear direction. The large gear 30a and the small gear 30b are integrally formed with each other. It is meshed with the pinion 29.

A drive gear 31 is rotatably supported inside the position near the rear end of the motor mounting plate 25, and a large gear 31a and a small gear 31b are integrally formed. The large gear 31a is meshed with the small gear 30b of the intermediate gear 30. The support shaft 32 supporting the drive gear 31 penetrates the drive gear 31 and projects inward.

The upper mounting piece 26 of the motor mounting plate 25 and the upper mounting piece 7 of the one support wall 2 are
The mounting pieces 27 on the lower side are fixed to the bottom plate portion 1a of the chassis 1 with screws 33, 33, respectively, whereby the motor mounting plate 25 is mounted on the chassis 1.

At this time, the support shaft 3 of the drive gear 31
The end portion of 2 is inserted into and supported by a support hole 34 formed below the bearing notch 3 of the one support wall 2. As a result, the small gear 31b of the drive gear 31 is positioned outside the one support wall 2 and immediately below the bearing notch 3. Therefore, as described above, the bearing members 13, 13 are supported by the bearing notch 3 and the thermal head 18 is elastically contacted, so that the bearing members 13, 13 are separated from the front edges 3a, 3a of the bearing notches 3, 3 and the head mounting plates 16, 16. The gear of the platen roller 10 which is in proper contact with the positioning edges 16a, 16a, that is, the platen gear 14 is the small gear 3 of the drive gear 31.
The driving force of the motor 28 is transmitted to the platen shaft 11 by being meshed with 1b. According to the support structure of the drive unit including the motor 28 and the like, the support holes 3 formed in the support wall 2 for positioning the platen roller 10 are formed.
Since the center of the drive gear 31 is accurately positioned by 4, the drive gear 31 and the platen gear 1 do not have to be so concerned about the accuracy of the other mounting portions of the motor mounting plate 25.
The meshing state with 4 is always correct.

In the heat-sensitive recording apparatus described above, however, the handle portion 23 of the release lever 22 is pressed downward to rotate the release lever 22 to separate the thermal head 18 from the platen roller 10. From the state where the thermal head 18 is separated from the platen roller 10, the arms 9, 9
When the platen roller 10 is rotated upward, the platen roller 10 easily comes out of the bearing notches 3 and 3, and the space between the platen roller 10 and the thermal head 18 is wide open.

Therefore, a heat-sensitive paper (not shown) is attached or replaced to position the heat-sensitive paper between the platen roller 10 and the thermal head 18. Then, the arms 9 and 9 are rotated downward so that the platen shaft 1 of the platen roller 10 is rotated.
1 is moved into the bearing notches 3, 3. Therefore, except for the force that moves the thermal head 18 rearward, the thermal head 18 moves substantially forward by the elastic force of the head pressing springs 21, 21 and the heating element 20 causes the platen roller 10 to move.
Since the platen roller 10 is elastically contacted with the surface of the platen roller 10 and presses the platen roller 10 substantially downward, the platen shaft 11, more specifically, the bearing members 13, 13 externally fitted to the platen shaft 11, of the bearing notches 3, 3. Front edges 3a, 3a and head mounting plates 16, 16
The platen shaft 11 is accurately positioned by contacting the positioning edges 16a, 16a.

The front edges 3a, 3a of the bearing notches 3, 3 and the positioning edges 16a, 16a of the head mounting plates 16, 16 rotate with the bearing members 13, 13 of the platen shaft 11 in contact with them. Alternatively, these portions may be covered with a material having excellent smoothness and abrasion resistance, such as Delrin, by outsert molding.

[0046]

As is apparent from the above description, in the thermal recording apparatus of the present invention, the chassis having an integral support wall erected from both side edges and the thermal head are rotatably supported with respect to the chassis. A head mounting plate, a bearing notch having a positioning portion for supporting the shaft of the platen roller formed on the support wall with a margin and positioning the shaft, and pressing the thermal head against the platen roller. A pushing spring for bringing the shaft of the platen roller into contact with the positioning portion is provided.

Therefore, in the thermal recording apparatus of the present invention,
Since the shaft of the platen roller is brought into contact with the positioning portion of the bearing notch formed on the support wall integrally erected on both side edges of the chassis for positioning, it is easy to obtain positioning accuracy, and the platen roller and the thermal head are Does not become non-uniform in the axial direction.

As shown in the above embodiment, if the head mounting plate is also provided with a positioning portion for the platen roller, the platen roller is centered by the member to which the thermal head is attached. Therefore, the positioning between the thermal head and the platen roller is performed more accurately.

It should be noted that the specific shapes and structures shown in the above embodiments are merely examples for embodying the present invention, and the technical scope of the present invention is limitedly interpreted by these. It is not something that will be done.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an example of implementation of a thermal recording apparatus of the present invention.

FIG. 2 is a plan view.

FIG. 3 is an enlarged left side view.

FIG. 4 is an enlarged right side view.

FIG. 5 is a rear view.

6 is a cross-sectional view taken along line VI-VI of FIG.

FIG. 7 is an enlarged side view of an essential part showing a state immediately before positioning the platen roller.

FIG. 8 is an enlarged side view of an essential part showing a state where the platen roller is positioned.

FIG. 9 is a side view showing an example of a conventional thermal recording apparatus.

[Explanation of symbols]

 1 Chassis 2 Support Wall 3 Bearing Notch 3a Positioning Section 10 Platen Roller 11 Platen Roller Shaft 16 Head Mounting Plate 18 Thermal Head 21 Push Spring

Claims (1)

[Claims] 1. A chassis having an integral support wall erected from both side edges, a head mounting plate for rotatably supporting the thermal head with respect to the chassis, and a margin for a platen roller shaft formed on the support wall. A bearing notch provided with a positioning part for supporting the shaft with the shaft and positioning the shaft,
A thermal recording apparatus comprising: a pressing spring that presses the thermal head against the platen roller to bring the shaft of the platen roller into contact with the positioning portion.