CN100475545C - roll paper printer - Google Patents

Abstract

A rolled sheet printer comprises a body unit and a closable cover unit mounted on the front face of a body unit closably to the front side. When the closable cover unit is opened, the front side of a rolled sheet storage part in a printer body is put into an opened condition to allow the replacement of the rolled sheet. A detecting protrusion of the rolled sheet detecting mechanism is protruded in the rolled sheet storage part. When the rolled sheet is running out, the position of its core hole lowers and the detecting protrusion is put into the core hole to detect that the rolled sheet is running out. When the closable cover unit is opened, a link lever is moved from a first position to a second position on the front side thereof and its abutting plate portion pushes the detecting protrusion therein to hold it in the condition being set out of the rolled sheet storage part. Thus, rolled sheet replacing work can be efficiently done without being disturbed by the detecting protrusion.

Description

roll paper printer

technical field

The present invention relates to a roll paper printer having a roll paper size detection device, the roll paper printer featuring an improvement enabling easy replacement of the roll paper.

Background technique

One type of roll paper printer has roll paper loaded such that the roll paper can simply be rolled on the bottom of the roll paper chamber. Roll paper generally has a long strip of recording paper wound into a roll around a hollow core with a hole in the center. Roll paper printers of this type also typically have roll paper size detection means for detecting the proximal end of the roll when a small amount of roll paper remains on the core. One type of roll paper size detection device has a rod inserted into a hole in a roll paper core.

The lever is pressed against the round end (side) of the roll paper held by the push member at a predetermined height above the bottom of the roll paper chamber in the roll paper chamber. When the outer diameter of the roll paper gradually decreases due to printing consumption, the position of the core hole also gradually decreases. When the amount of roll paper decreases so that the core hole has dropped to a predetermined height, the detection rod slides off from the round end of the roll paper and is inserted into the core body of the roll paper. The detection lever is not limited to a mechanism for inserting the lever into the roll paper core, but may be a mechanism for separating the lever from the round end of the roll in the outer circumferential direction of the roll. The amount of remaining roll paper can be known to be small by using a mechanical or other type of detection switch to detect movement of the detection rod separating from the round end of the roll paper into the core hole or to the outer surface of the roll.

A concave groove into which the rolled paper falls once the diameter of the rolled paper has been reduced and an inclined guide surface to guide the rolled paper into the groove are formed at the bottom of the rolled paper chamber. By guiding the roll paper along these inclined surfaces into the concave grooves, the roll paper can be held in a position detectable by the detection lever, and the proximal end of the roll paper can also be reliably detected.

JP-A 9-254474 and JP-A 2003-11453 teach a roll paper printer having a roll paper chamber and a roll paper size detection device that detects the proximity of the roll paper using this type of detection lever. end.

When there is no roll paper in the roll paper chamber, the detection rod of the roll paper detection device protrudes into the roll paper detection chamber. When loading a roll, for example when changing a roll, the user must therefore use the end of the roll to push the detection lever and retract the detection lever from the roll chamber to put the roll into the roll chamber. If the detection rod is inserted into the core hole when the roll paper is removed, it is also necessary to push the detection rod to this side and retract the detection rod so that the roll paper can be removed.

If the roll is loaded or removed quickly when loading or removing the roll, the detection lever cannot be retracted as fast, causing the detection lever to jam on the roll and interfere with loading and removing the roll. The detection rod may even be damaged.

In order to make loading and removing roll paper easier, a taper with a large angle in the direction of roll paper loading and removal must be provided/presented on the detection lever so that the detection lever can be pushed and retracted smoothly. However, providing a taper with a large angle on the detection rod causes a problem of lowered detection accuracy because it is more difficult to set a point where the detection rod is accurately inserted into the roll paper core when the roll paper is reduced to a predetermined remaining volume than with a detection rod that does not have a taper. many. The same problem also arises with a mechanism in which the detection lever is separated from the outer circumference of the roll paper.

Contents of the invention

It is therefore an object of the present invention to provide a roll paper printer having a precision roll paper detection device which does not interfere with loading and removing roll paper.

To achieve this object, a roll paper printer according to a preferred aspect of the present invention includes a roll paper storage unit having a bottom surface on which the roll paper is held and rolled; operable a cover unit that is operable to open and close a roll paper loading opening to the roll paper storage unit; a roll paper size detection mechanism that includes a detection lever capable of protruding to A pushing member that moves in a direction inside the roll paper storage unit and in a direction retracted from the roll paper storage unit, and pushes the detection lever in the protruding direction, is characterized in that, when stored in when the outer diameter of the roll paper in the roll paper storage unit is reduced to a predetermined size or less, the detection lever is separated from the roll paper and pushed in the protruding direction; and the detection lever retracting mechanism, The detecting rod retracting mechanism is used to link with the opening of the operable cover unit, resist the pushing force of the pushing member, and move the detecting rod protruding into the roll paper storage unit in the retracting direction.

Opening the operable cover unit of the roll paper printer according to this aspect of the invention causes the detection lever to move in a retraction direction in which the detection lever is retracted from the roll paper chamber. By properly setting the distance that the detection rod moves in the retracting direction, the roll paper will not contact the detection rod when being loaded into the roll paper chamber. Also, when the roll is removed because the roll is empty or nearly empty, when the sensing lever is inserted into the core of the roll, the sensing lever will be fully retracted from the core to a position where the sensing lever will not interfere with the roll, and The roll paper or core is thus easily removed. The detection lever is thus prevented from contacting the roll paper and interfering with the ease of loading or removing the roll paper from the roll compartment.

There is also no need for tapered or sloped surfaces on the sensing rod so that the roll paper pushes the sensing rod out of the way smoothly when the roll is loaded or removed. Therefore, the near-end detection accuracy of the detection rod can be improved.

The detecting lever retracting mechanism in another aspect of the present invention operates in conjunction with the opening and closing action of the operable cover unit, and includes a first position separated from the detecting lever (a position where the detecting lever is protruded) and a retracting direction. A moving plate that moves bidirectionally between the second position (the position where the detection rod is retracted) by pushing up the detection rod.

Further preferably, the detecting rod retracting mechanism includes a pushing member for pushing the moving plate toward the first position. When the operable cover unit is opened, the force of the pushing member acts on the operable cover unit in a closing direction of the operable cover unit. Therefore, when the operable cover unit is set to open toward the front of the printer, damage due to the operable cover unit being opened by forcibly hitting the surface on which the printer is installed can be prevented. The force of the cover unit and the thrust of the push member cooperate together to cause the operable cover unit to be suddenly forced open.

Further preferably, the detection lever of the detection lever retracting mechanism is pressed against the round end (side) of the roll paper stored in the roll paper storage unit, and when the outer diameter of the roll paper is reduced to a predetermined size or less, the detection is performed. The rod separates from the round end of the roll and is pushed in said protruding direction.

The detection rod may be positioned, for example, such that the detection rod is pushed in a protruding direction to separate from the inner circumferential edge of the round end of the roll and enter a core hole positioned in the center of the round end of the roll.

In the roll paper printer according to this aspect of the present invention, the roll paper storage unit stores roll paper, and the rotation axis of the roll paper is aligned with the width direction of the printer; the protruding direction and the retracting direction of the detection lever aligned with the width direction of the printer; the roll paper loading opening is formed on the roll paper storage unit at the front side of the printer; and the operable cover unit is capable of facing toward the front of the printer pivoted about a bottom end portion of the operable cover unit The portion is opened, and has a platen member defining a printing position of a print head attached to a top end portion of the operable cover unit.

In the roll paper printer according to this aspect of the present invention, the detection lever retracting mechanism operates in conjunction with opening and closing of the operable cover unit, and includes a retracted position separated from the detection lever when the operable cover unit is closed (so that A position where the detection lever protrudes) and a forward position where the detection lever is pushed in the retracted direction (position where the detection lever is retracted) when the operable cover unit is opened, bidirectionally moves in the front-rear direction. When the operable cover unit is closed, the moving plate moves toward the rear of the printer to the retracted position, and is separated from the detection lever. The detection lever is thus pushed in the protruding direction, pressed against the round end of the roll paper, and the size (near end) of the roll paper can be detected. When the operable cover unit is opened, the moving plate moves toward the front of the printer to the advanced position, and pushes the detection lever to the retracted position, thereby retracting the detection lever from the roll paper chamber.

The detection lever retracting mechanism preferably has an urging member for urging the moving plate toward the rear of the printer.

The detection lever of the roll paper size detection mechanism may be configured to be pushed in a protruding direction when the detection lever is separated from the circumferential edge of the round end of the roll paper. More specifically, when the roll paper approaches the end, the detection lever separates from the outer circumferential edge of the round end of the roll paper and moves to the outer circumferential surface of the roll paper, thereby detecting the proximal end of the paper roll.

In the roll paper printer, further preferably, the roll paper storage unit stores the roll paper, and the rotation axis of the roll paper is aligned with the width direction of the printer; when the detection lever is separated from the outer peripheral edge of the end of the roll paper and moves When reaching the outer circumferential surface of the roll paper, the detection lever is pushed in the protruding direction; the operable cover unit can pivotally open toward the front of the printer around the bottom end portion of the operable cover unit, and has a pressure that defines the printing position of the print head. A paper member, the paper pressing member is attached to the top end of the operable cover unit; the roll paper stored in the roll paper storage unit is pressed to the side of the operable cover unit while advancing toward the printing position.

When the recording paper is pulled from the roll paper and advanced to the printing position, the roll paper is pressed against an operable cover unit located in front of the roll paper chamber. As a result, the roll paper positioned and rolled on the bottom of the roll chamber does not roll back and forth in the roll chamber and is held at the forward position.

In order that the roll paper can be held at a predetermined position within the roll chamber, generally a concave groove is formed on the bottom of the roll chamber and an inclined guide surface guides the paper roll into said concave groove as the roll diameter decreases. . However, forming the concave groove and the inclined guide surface increases the vertical size of the paper roll chamber, thus hindering downsizing of the printer. This is particularly disadvantageous in reducing the height of printers having an operable cover unit arranged to the front of the printer to pivot at the bottom and open towards the front of the printer so that the roll can be changed in the roll compartment from the front of the printer.

For example, when the printer is used to print receipts and is installed on the lower shelf under the counter of a fast food restaurant, the printer must be short. In addition, the paper outlet must be provided at the top of the printer facing forward so that the operator can easily remove the printed paper from the front of the printer.

The arrangement of the present invention does not require the presence (formation) of concave grooves and inclined guide surfaces in the bottom of the roll chamber, and makes the bottom of the roll chamber flat. The present invention thus suppresses an increase in the height of the roll paper printer while still maintaining the roll paper at a predetermined position in the roll paper chamber, thereby enabling reliable detection of the proximal end of the roll paper.

Preferably, an upwardly facing tapered surface rising toward the top of the printer is formed at a front end portion facing the detection lever of the operable cover unit; The cover unit enables the roll paper disposed between the upward-facing tapered surface and the operable cover unit to move through the upward-facing tapered surface to the rear side of the detection lever.

The arrangement avoids the problem that the operable cover unit cannot be fully closed because, when the operable cover unit is closed, the detection lever protrudes into the roll paper chamber before the roll paper is stored in the roll paper chamber, and the roll paper becomes must remain between the front of the detection lever and the operable cover unit.

Further preferably, a rearwardly facing tapered surface facing the rear of the printer is formed on a side facing the detection lever on an inner side of the roll paper size unit; The outer edge portion of the end of the roll paper.

If the roll paper moves to the rear of the roll chamber so that the detection lever separates from the end, and the roll paper then moves from the rear to the front, the arrangement is such that the outer peripheral edge of the roll contacts the rearwardly facing tapered surface, so that the roll paper is easily Move forward while pushing the detection lever in the retracted direction and return the detection lever to the position where it presses against the round end of the roll.

Further preferably, a tapered guide surface facing the inner side in the width direction of the printer is formed on the top of the detection lever; and the tapered guide surface can contact the outer side of the end of the roll paper moving downward from the top of the detection lever. Circumferential edge.

The aspect of the invention ensures that the outer peripheral edge contacts the tapered guide surface if the rolled paper stays on the detection lever when the operable cover unit is closed. The weight of the roll paper thus pushes down onto the tapered guide surface, thereby pushing the detection lever in the retracted direction, while the roll paper drops to the bottom of the roll chamber and away from the detection lever which presses against the round end of the roll .

Other objects and accomplishments, together with a more complete understanding of the invention, will become apparent and understood by referring to the following description and claims when taken in conjunction with the accompanying drawings.

Description of drawings

Fig. 1 is an external oblique view of a roll paper printer according to a first embodiment of the present invention.

Fig. 2 is an external perspective view showing the roll paper printer with the operable cover opened.

Fig. 3 is a schematic diagram showing the internal arrangement of the roll paper printer.

Fig. 4 is a side view of the roll paper printer with the operable cover unit and the printer casing removed.

5A and 5B are a perspective view and a side view, respectively, of the web press machine shown in FIG. 4 with one side plate removed to describe the internal structure.

6A and 6B are a perspective view and a side view, respectively, of the roll paper printer with the operable cover unit opened.

7A to 7C show a perspective view, a plan view, and a side view of the roll paper detection mechanism, respectively.

8A to 8C respectively show an oblique view, a plan view, and a side view of the roll paper detecting mechanism with the operable cover opened.

Fig. 9 is a perspective view of a roll paper printer according to a second embodiment of the present invention.

Fig. 10 is a perspective view of a mechanical part of the printer seen from the front left.

Fig. 11 is a perspective view of the mechanical part of the printer seen from the front right.

Fig. 12 is a perspective view of the mechanical part of the printer with the operable cover unit opened.

Fig. 13 is a schematic sectional view of a mechanical part of the printer.

14A to 14C are a perspective view of the roll paper size detecting mechanism seen from above, a perspective view seen from below, and a perspective view of the detection lever.

15A and 15B are schematic sectional views of a printer mechanism portion describing the operation of the roll paper size detection mechanism.

Figure 16 describes the operation of the detection rod retraction mechanism.

Fig. 17 describes a method of setting the inclination angle of the detection rod contact surface.

18A and 18B are perspective views showing variations of the roll paper size detection mechanism.

Detailed ways

Preferred embodiments of the roll paper printer according to the present invention will be described below with reference to the accompanying drawings.

*first embodiment

A roll paper printer according to a first embodiment of the present invention will be described below with reference to FIGS. 1 to 8 .

* General configuration

1 is an external perspective view of a roll paper printer according to the present invention, and FIG. 2 is a perspective view showing the roll paper printer when an operable cover is opened.

The roll paper printer 1 according to this embodiment of the present invention has a printer frame 2, and an operable cover unit 3 is attached to the front. An operation panel unit 4 is provided to a front corner of the printer chassis 2 . A paper outlet 5 extending in the printer width direction is formed at the top of the operable cover unit 3 in front of the printer.

The printer chassis 2 is covered by a box-shaped printer case 6 that is long in front and rear, and is opened on the front and bottom sides. An operable cover case 7 defining the front of the printer is attached to the front of the operable cover unit 3 . Operating the operating lever 8 located at the operating panel unit 4 releases an unillustrated cover lock, thereby releasing the operable cover unit 3 and causing the operable cover unit 3 to swing forward and pivot on the bottom end of the operable cover unit 3 Turn on. Opening the operable cover unit 3 opens the roll paper loading opening 9a at the front of the inner roll paper chamber 9 so that the roll paper 10 can be replaced.

A status indicator group 4 a of LEDs such as a feed button 4 b and a power switch 4 c are provided on the front of the operation panel unit 4 .

As further described below, a roll paper size detection mechanism for detecting when the roll paper stored inside is reduced to a predetermined size (predetermined diameter) is also provided in the roll paper chamber 9 . When an unillustrated control unit provided inside the roll paper printer 1 detects that the roll paper has decreased to or below a predetermined amount, the indicators in the drive status indicator group 4a are lit steadily or blink, for example, to notify the user. If the roll paper printer 1 is connected to a terminal device not shown, for example, the message can also be presented on the terminal device.

FIG. 3 is a schematic diagram of the inside of the roll paper printer 1 . The roll paper compartment 9 formed in the roll paper printer 1 is surrounded by a curved bottom plate 12 extending in the width direction of the printer, a top plate 13 extending in the width direction of the printer, and a front plate 14 extending in the width direction of the printer. , and generally conform to the shape of the roll paper 10. The roll paper 10 is held so that it can rotate freely on the paper guide bottom 12 within the roll paper chamber 9 .

The core hole 101 is provided at the center of the roll paper 10 . The web of recording paper 10a conveyed from the roll paper 10 is drawn to the front, passes through the printing position between the platen roller 15 and the thermal head 16, and is discharged to the front of the printer from the paper outlet 5 provided in front of the printing position. A scissors-type paper cutting device 20 is provided in front of the paper outlet 5 .

The paper cutting device 20 has a fixed blade 21 provided on the printer chassis 2 side, a movable blade 22 , and a movable blade drive mechanism 23 provided on the operable cover unit 3 side. The fixed blade 21 is arranged substantially horizontally in the width direction of the printer with a cutting edge (cutting edge) 21 a facing forward. The movable blade 22 is disposed substantially perpendicular to the width direction of the printer with the cutting edge 22 a facing upward at a position substantially directly below the cutting edge 21 a of the fixed blade 21 . When the recording paper 10a is conveyed between these cutting edges 21a and 22a (paper cutting position), the movable blade 22 on the bottom pivots upward so that the cutting edges 21a and 22a approach in the width direction of the printer, and cut recording paper 10a between them.

Fig. 4 shows a side view of the mechanical part of the roll paper printer 1 with the printer housing 6 and the operable cover housing 7 removed. 5A and 5B are a perspective view and a side view, respectively, in which one side panel indicated by a dotted line is removed to show the internal structure. 6A and 6B are oblique and side views, respectively, similar to FIG. 5 but with the operable cover unit open.

The web press 1 will be further described with reference to these drawings.

The printer chassis 2 has a base plate 31 defining the bottom of the printer, left and right side plates 32 and 33 vertically raised from the base plate 31 with a certain gap therebetween, and disposed between the rears of the left and right side plates 32 and 33 in the printer width direction. Between the backplane 30. The head mounting plate 34 is arranged horizontally across the gap between the tops of the side plates 32 and 33 in the width direction of the printer. The thermal print head 16 is mounted to the bottom of the head mounting plate 34 with the head surface 16a facing downward and generally horizontal (see FIG. 3 ). The top plate 13 of the roll paper chamber 9 is located under the back of the head mounting plate 34 . The bottom plate 12 of the roll paper chamber 9 rests on top of the base plate 31 .

The fixed blade mounting plate 35 is horizontally arranged above the head mounting plate 34 in the width direction of the printer. The fixed blade 21 of the paper cutting device 20 is generally horizontally connected to the front bottom of the fixed blade mounting plate 35 and faces forward. The fixed blade mounting plate 35 is disposed between the top edges of the left and right pivot plates 36 , 37 (only the pivot plate 37 is shown in the figure) which are located outside the side plates 32 and 33 . The pivot plates 36, 37 are able to pivot (move) slightly in the longitudinal direction (rearward direction) of the printer on bottom end portions 36a, 37a of the pivot plates 36, 37 (only the bottom 37a is shown in the figure). When the paper cutting device 20 cuts the recording paper 10a, the movable blade 22 pivots upward from below while pushing (moving) the fixed blade 21 to the rear so that the cutting edges 21a and 22a contact at one point and cut the recording paper 10a. The pivot plates 36, 37 support the fixed blade 21 so that the fixed blade 21 retracts slightly while cutting the paper.

A roll paper size detection mechanism 50 for detecting when the supply of roll paper 10 held in the roll paper chamber 9 drops to or below a predetermined amount is fitted to the bottom end portion on the outer side of the side plate 33 .

The operable cover unit 3 can be opened at a predetermined angle to the front of the printer pivoted on support pins 41 , 42 fixed to bottom end portions of the side plates 32 and 33 of the printer chassis 2 . The operable cover unit 3 has a front plate portion 43 and narrow side plate portions 44 and 45 formed by vertically bending the left and right edges of the front plate portion 43 toward the rear of the printer. The movable blade 22 and the movable blade drive mechanism 23 of the paper cutting device 20 are provided to the front of the front plate portion 43 and covered with a protective plate 24 . The front of the protective plate 24 is covered by an operable cover case 7 (see FIG. 3 ). The platen roller 15 is provided to freely rotate between the side plate portions 44 and 45 . The front plate 14 of the roll paper chamber 9 fixed to the back of the front plate portion 43 is located below the platen roller 15 .

As described above, the front plate 14 of the roll paper chamber 9 , the platen roller 15 , and the movable blade 22 of the paper cutting device 20 are installed in the operable cover unit 3 . Opening the operable cover unit 3 opens the paper conveying path as shown in FIGS. 2 and 5 , and opens the paper conveying path from the roll paper chamber 9 to the paper outlet 5 through the printing position and the paper cutting device. Therefore, when a certain length of recording paper 10a is pulled from the roll paper 10 in the roll paper chamber 9 and then the operable cover unit 3 is closed, the recording paper 10a is automatically set and passes through the paper transport path.

*Roll paper size detection mechanism

7A, 7B, and 7C are partial oblique views, plan views, and side views of the roll paper size detection mechanism 50 . 8A, 8B, and 8C are partial perspective views, plan views, and side views of the roll paper size detection mechanism 50 when the operable cover unit 3 is opened.

The roll paper size detection mechanism 50 will be described with reference to FIGS. 4 to 8 . The roll paper size detection mechanism 50 has a detection lever 51 attached to the outside of the side plate 33 of the printer chassis 2 . The end of the detection lever 51 toward the rear of the printer can pivot in the width direction of the printer on a post 52 connected to the side plate 33 . A torsion spring 52a (pushing member) is provided to the post 52, and the torsion spring 52a continuously pushes the detection lever 51 inside in the printer width direction (projection direction).

A detection protrusion (tab) 53 protruding to the inside in the printer width direction is connected to the distal end portion of the detection lever. The detection protrusion 53 protrudes into the roll paper chamber 9 through an opening not shown in the side plate 33 . The bottom plate 12 of the roll paper chamber 9 is slightly inclined forward, and gradually decreases in diameter as the roll paper 10 located thereon is used (consumed), so that the core hole 101 gradually descends to the front. When the diameter of the roll paper 10 is reduced to a predetermined size, the core hole 101 of the used roll paper 10A reaches the position 101A including the position where the detection protrusion 53 protrudes.

The detection protrusion 53 remains pressed against the round end 10b (side) of the rolled paper 10 held in the rolled paper chamber 9 until the diameter of the rolled paper 10 is reduced to a predetermined size. When the core hole 101 of the roll paper 10 is lowered to a predetermined height, which is the position where the detection protrusion 53 protrudes, the detection protrusion 53 enters the core hole 101 .

The base end of the detection lever 51 is connected to one switching portion 54 a of the detection switch 54 . When the detection protrusion 53 is pressed against the round end 10b of the roll paper 10, the detection switch 54 is turned off. When the detection protrusion 53 is inserted into the core hole 101 of the roll paper 10, the detection lever 51 pivots, and the detection switch 54 connected to the detection lever 51 is turned off. A control unit not shown detects the output (change) from the detection switch 54 and knows that the diameter of the roll paper 10 has been reduced to a predetermined size, so only a small amount of recording paper 10a remains and that the roll paper 10 will soon need to be replaced.

The roll paper size detection mechanism 50 according to the present embodiment of the present invention has a detection lever retraction mechanism 55 for unconditionally retracting and protruding from the roll paper chamber 9 in conjunction with opening the operable cover unit 3 to the detection protrusion 53 of the detection lever 51 in the roll paper chamber 9 .

* detection rod retraction mechanism

The detection lever retraction (withdrawal) mechanism 55 according to the present embodiment of the present invention has a retracted (withdrawal) position (first position) A away from the detection protrusion 53 and a function of pushing the detection protrusion 53 in the retracting direction. The link 72 reciprocates between the forward position (second position) B. The tension spring 67 (pushing member) pushes the link 72 to the retracted position A. As shown in FIG.

The distal end portion 72 a of the link 72 is connected to freely rotate on the support pin 69 fixed to the side plate portion 45 of the operable cover unit 3 . A long straight slit 72 b is formed in the rear of the link 72 in the front-rear (longitudinal) direction of the printer. The slide pin 65 fixed to the side wall portion 63 of the bottom plate 12 of the roll paper chamber 9 is slidably inserted into the slot 72b. Tension spring 67 is tensioned between slide pin 65 and a position on the bottom end of back plate 30 of printer chassis 2 .

Opening and closing the operable cover unit 3 moves the link 72 bidirectionally in the longitudinal direction to the printer between the retracted position A ( FIG. 7 ) and the advanced position B ( FIG. 8 ). A wide portion is formed in the middle of the link 72, and the contact plate portion 72c extending toward the bottom moves along a path passing the position where the detection protrusion 53 protrudes. When the link 72 is in the retracted position A (when the link 72 is in the closed position 3A shown in FIG. 1 ), the contact plate portion 72c is offset to the detection protrusion 53 as shown in FIGS. 7B and 7C. rear side. When the link 72 is then moved to the advanced position B, the detection protrusion 53 is pushed to the outside by the contact plate portion 72c, contacts the outside of the contact plate portion 72c, and thus the detection protrusion 53 is held in the retracted position by the contact plate portion 72c. When the operable cover unit 3 is closed from the open position 3B, the link 72 is also returned from the advanced position B to the retracted position A, and the detection protrusion 53 is separated from the contact plate portion 72c, thereby protruding into the roll paper chamber 9 again.

Accordingly, the detection protrusion 53 of the detection lever 51 is retracted from the roll paper chamber 9 in conjunction with opening the operable cover unit 3 . Therefore, when the roll paper 10 is replaced, the detection protrusion 53 is removed from the inside of the roll paper chamber 9 , thus preventing the detection protrusion 53 from contacting the roll paper 10 and hindering the replacement of the roll paper 10 .

Since the detection protrusion 53 is thus retracted, there is no need to form a tapered or inclined surface on the distal end portion of the detection protrusion 53 in order to push the detection protrusion 53 out of the way when the roll paper is replaced. Also, since the tapered or inclined surface can be omitted, the detection accuracy of the detection protrusion 53 can also be improved.

Note that, as shown in FIG. 7 , tapered portions 53 a and 53 b toward the front and back of the printer are formed on the outer side surface of the distal end of the overall cylindrical detection protrusion 53 . The front tapered portion 53 a is provided to prevent interference with the edge of an opening not shown in the side plate 22 , and the rear tapered portion 53 b is provided to facilitate pushing by the contact plate portion 72 c of the link 72 . Tapered portions are not formed on the outside surfaces 53c and 53d perpendicular to the tapered portions 53a and 53b, that is, not formed on the sides in the moving direction of the core hole 101 of the roll paper 10 (arrow C in FIGS. 5B and 7 ). )superior. Since the tapered portion is not formed on either side in the roll paper detecting direction, the detection accuracy is improved compared to an arrangement having the tapered portion on these surfaces.

*Roll paper discharge mechanism in the roll paper chamber

In the roll paper compartment 9 according to the present embodiment of the invention, the bottom plate 12 is changed from a substantially horizontal posture to a forwardly inclined posture in conjunction with opening and closing the operable cover unit 3 . When the operable cover unit 3 is opened, the bottom plate 12 is tilted forward, and the roll paper 10 resting on the bottom plate 12 rolls forward due to its own weight. In this embodiment of the invention, the portion using the detection lever retraction mechanism 55, including the linkage 72 and the tension spring 67, constitutes the mechanism for ejecting the roll paper 10, as further described below.

The roll paper discharge mechanism will be described mainly with reference to FIGS. 3 , 5A, 5B, 6A, and 6B. The bottom plate 12 is supported on the base plate 31 so that the front end side can freely circulate on the support pins 61 in the front-rear direction of the printer. Slide pins 64 , 65 (only the slide pin 65 is shown in the figure) are fixed so as to protrude to the sides behind the side wall portions 62 , 63 on both sides of the bottom plate 12 .

Tension springs 66 and 67 (only tension spring 66 is shown in the figure) are tensioned and connected between these sliding pins 64 , 65 and a location at the bottom end of back plate 30 . These left and right tension springs 66 and 67 hold the bottom plate 12 in a substantially horizontal position 12A in contact with the base plate 31 .

Links 71 and 72 of the same shape are provided between these slide pins 64 , 65 and vertical center portions of the left and right side plate portions 44 and 45 of the operable cover unit 3 . The distal ends 71a and 72a of the links 71 and 72 are connected to the support pins 68 and 69 so that the links 71 and 72 can freely pivot to the printer. Long straight slots 71b and 72b are formed in the rear end portions of the links 71 and 72 in the front-rear direction of the printer, and slide pins 64, 65 are inserted to slide freely in these slots. These slide pins 64, 65 are also inserted into arc-shaped guide holes 73 and 74 (only the guide hole 74 is shown in the figure) formed in the left and right side plates 32 and 33 as shown in FIG. 4 . These guide holes 73 and 74 are arc-shaped with the support pin 61 at the center. When the bottom plate 12 pivots on the support pin 61 , the slide pins 64 , 65 move along these guide holes 73 and 74 .

Next, the operation of the roll paper discharge mechanism thus formed in the roll paper chamber 9 will be described.

When the operable cover unit 3 is closed, the left and right slide pins 64 , 65 of the bottom plate 12 are positioned at the front ends of the slots 71 b and 72 b in the left and right links 71 and 72 . As shown in FIG. 4 , the slide pins 64 , 65 are positioned at the bottom ends of the arc-shaped guide holes 73 and 74 .

When the operable cover unit 3 is opened, the left and right slide pins 64 , 65 whose front ends are connected to the left and right side plate portions 44 and 45 of the operable cover unit 3 also move forward. The left and right slide pins 64 , 65 connected to the bottom plate 12 of the roll chamber 9 are positioned at the front ends of the slots 71 b and 72 b in the links 71 and 72 . The bottom plate 12 does not move until the links 71 and 72 move forward by a predetermined distance and the rear ends of these slots 71 b and 72 b contact the slide pins 64 , 65 .

After the slide pins 64 , 65 contact the rear ends of the slits 71 b and 72 b , as the operable cover unit 3 continues to open, the left and right links 71 and 72 pull the slide pins 64 , 65 forward. As a result, the bottom plate 12 to which these slide pins 64 , 65 are connected can circulate on the front support pin 61 and thus swing forward on the support pin 61 in conjunction with opening the operable cover unit 3 .

As shown in FIG. 6 , when the operable cover unit 3 is in the fully open position at the open position 3B, the bottom plate 12 is inclined at a predetermined angle in a forwardly inclined position 12B. As a result, in conjunction with opening the operable cover unit 3 , the bottom plate 12 changes from the substantially horizontal position 12A to the forwardly inclined position 12B. When the roll of paper 10 is on the base plate 12, the weight of the roll of paper 10 causes the roll of paper 10 to roll forward on the base plate 12 to the forwardly inclined position 12B. As a result, the roll paper 10 having less remaining recording paper 10a is ejected to the front as indicated by the dotted line in FIG. 6 . Therefore, it is easy to remove the rolled paper 10 from the top front portion of the opened operable cover unit 3 .

After the bottom plate 12 starts to pivot, the operable cover unit 3 is pulled rearward by the left and right tension springs 66 and 67 through the inserted links 71 and 72 . The tension of the tension springs 66 and 67 thereby prevents the operable cover unit 3 from suddenly opening forward when the operable cover unit 3 is opened, thereby preventing damage due to the operable cover unit 3 hitting the surface on which the printer is placed with great force.

When the operable cover unit 3 is then closed, the links 71 and 72 also move to the rear in conjunction with the closing of the operable cover unit 3 . The forward tension on the left and right slide pins 64, 65 of the bottom plate 12 is thereby released, and the force of the tension springs 66 and 67 returns the bottom plate 12 to the original generally horizontal position 12A. As a result, the rolled paper 10 resting on the bottom plate 12 is stored in a predetermined position.

*Second embodiment

A roll paper printer according to a second embodiment of the present invention will be described below with reference to FIGS. 9 to 16. FIG.

9 is an external perspective view of the roll paper printer, FIG. 10 is a perspective view of the printer mechanism seen from the left front, and FIG. 11 is a perspective view of the printer mechanism seen from the right front. Fig. 12 is a perspective view of the printer mechanism when the operable cover unit is opened, and Fig. 13 is a schematic diagram of the internal arrangement of the roll paper printer.

The roll paper printer 100 according to this embodiment of the present invention has a printer mechanism unit 200, a printer case 102 covering substantially the entirety of the printer mechanism unit 200, and an optional cover covering the front of the printer mechanism unit 200 that is not covered by the printer case 102. The cover case 103 is operated. A paper outlet 108 extending in the width direction of the operable cover case 103 is formed at the top of the operable cover case 103 .

The printer housing 102 covers part of the front, top, right, left, and rear of the printer mechanism unit 200 . A power switch 104 for turning on and off the roll paper printer 100, a status indicator group 105 for reporting the operating status of the roll paper printer 100, and a roll paper 106 for feeding the roll paper held in the roll paper press 100 The feed button 107 is provided on the front of the printer housing 102 .

The printer mechanism unit 200 includes a printer chassis 101a and an operable cover unit 101b. The operable cover unit 101 b includes an operable cover 109 and an operable cover case 103 connected to the front of the operable cover 109 . The operable cover unit 101b is hinged to the front bottom of the printer mechanism unit 200, and can be swung forward and opened on the hinge. Operating the operating lever 120 provided on the front of the printer housing 102 releases a cover lock not shown, and enables the operable cover 109 to swing from the closed position shown in FIGS. 10 and 11 on the bottom end portion of the operable cover 109 to the open position shown in Figure 12. When the operable cover 109 is opened, the roll paper loading opening 121a in front of the roll paper compartment 121 formed in the printer chassis 101a is opened as shown in FIG. 12 so that the roll paper 106 can be replaced. Roll paper 106 is typically a tape of recording paper (thermal paper in this embodiment of the invention) wound around a core.

As shown in FIG. 10, FIG. 11, and FIG. 12, the printer frame 101a has a base plate 125, left and right side plates 126 and 127 vertically rising from the left and right sides of the base plate 125, arranged on the width direction of the printer. A back plate (not shown) between the back surfaces of the left and right side plates 126 and 127 , and a top plate 128 horizontally disposed between the tops of the side plates 126 and 127 in the printer width direction.

A roll paper holder 129 forming the bottom and rear of the roll paper chamber 121 extends between the left and right side plates 126 and 127 . The operable cover unit 101b is fixed on the support shaft 130 between the front ends of the left and right side plates 126 and 127 so that the operable cover unit 101b can be pivotally opened on the support shaft 130 .

The operable cover unit 101b has a front plate portion 131 and side plate portions 132a and 132b bent from both sides of the front plate portion 131 at right angles to the back of the printer. A paper cutting device 134 having an inner movable blade 133 is provided to the top outside of the front plate portion 131, and a fixed blade 135 is provided above the paper cutting device 134 with the paper outlet 108 interposed therebetween. The fixed blade 135 is supported by a fixed blade support frame (not shown in the figure) provided on the top of the printer chassis 101a. The front end (leading end) of the roll paper 106 passes between the movable blade 133 and the fixed blade 135 to come out of the paper outlet 108 . To cut the web 106 , the movable blade 133 pivots up to the fixed blade 135 and cooperates with the movable blade 133 to cut the web 106 .

As shown in FIGS. 12 and 13 , a platen roller 136 is freely rotatably disposed between the tops of the side plate portions 132 a and 132 b of the operable cover unit 101 b. When the operable cover unit 101b is closed, as shown in FIG. 13, a thermal (sensitive) print head 137 is disposed above the platen roller 136 at a position opposite to the platen roller 136, and a plurality of heat-resistant elements are disposed on the thermal printing plate. on the bottom of the head 137. The roll paper 106 accommodated in the roll paper chamber 121 is held between the platen roller 136 and the thermal printer head 137, and is conveyed to the paper outlet 108 by rotating the platen roller 136 by a motor not shown.

When the roll paper 106 passes between the platen roller 136 and the thermal head 137 , text and images are printed on the roll paper 106 by heat emitted from the heat-resistant element of the thermal head 137 . The thermal print head 107 is located on the head mounting plate 138 arranged under the printer housing 102, and the head mounting plate 138 includes a head support plate 139 for supporting the thermal print head 137 and a screw 138a connected to the head support plate 139. Spring support plate 140 .

As shown in FIG. 13 , a first paper guide 151 for guiding the roll paper 106 to the platen roller 136 is provided under the head mounting plate 138 . The first paper guide 151 includes a bent portion 151a whose distal end portion is bent upward and extends. The bent portion 151 a is located immediately behind the platen roller 136 . The roll paper 106 is bent upward at the bent portion 151 a and then guided to the platen roller 136 . This prevents wrinkling of the edges of the roll paper when force is applied to the roll paper 106 from the side.

A front panel 141 forming a rear surface of the operable cover unit 101b is fixed inside the operable cover unit 101b. The front plate 141 includes a base portion 141a disposed at an angle toward the rear of the printer and a bent portion 141b continuous with the base portion 141a and bent to the rear. When the roll paper 106 is consumed to such a size that the roll paper 106 does not contact the first paper guide 151 when the paper is conveyed, the second paper guide 152 provided to the top end of the bending portion 141b contacts the roll paper 106 and bends the roll paper 106 .

The second paper guide 152 is fixed so that it can pivot on a support pin 153, and is pushed to the rear by an unshown urging member. The second paper guide 152 also prevents wrinkling of the edges of the roll paper.

The rolled paper chamber 121 is provided between the rolled paper holder 129 and the front plate 141 of the operable cover unit 101b. The roll paper holder 129 includes a bottom portion 129a slightly inclined toward the front and a rear portion 129b curved upward and extending from the rear end of the bottom portion 129a.

The roll paper 106 held in the roll paper chamber 121 is conveyed from the roll rear side through the paper outlet 108 at the roll front, and is discharged from the front of the roll paper printer 100 . As a result, the outside of the rolled paper 106 is pushed against the front plate 141 as the rolled paper 106 is discharged from the paper outlet 108 . Regardless of the size of the roll, the roll paper 106 can always be supported by the bottom 129a of the roll paper holder 129 and the operable cover unit 101b.

The first roller 142 extending in the printer width direction is provided to the base 141a of the front plate 141 in the middle between the top and bottom of the base 141a, and substantially in the center in this embodiment of the invention. In the present embodiment of the present invention, the second roller 143 extending in the printer width direction is disposed below the first roller 142 at the bottom end portion of the base 141 a. More specifically, openings 144 and 145 are formed in the width direction of the printer in the base 141 a of the front plate 141 , and shaft portions of these first and second rollers 142 and 143 are supported on the sides of these openings 144 and 145 . These first and second rollers 142 and 143 have the same diameter, and the outer peripheral surfaces of the rollers protrude beyond the surface of the base 141 a of the front plate 141 .

As shown in FIG. 13, when the outer diameter of the rolled paper 106 is large, specifically, in an embodiment of the present invention, when the diameter of the rolled paper 106 is between a maximum diameter of about 83 mm and about 50 mm, the first Roller 142 contacts roll paper 106 and reduces rolling resistance of roll paper 106 rolling within roll paper chamber 121 .

When the roll paper 106 is consumed such that the diameter of the roll paper 106 is less than about 50 mm, the second roller 143 then contacts the outside of the roll paper 106 and also reduces the rolling resistance of the roll paper 106 rolling within the roll paper chamber 121 .

When the diameter of the roll paper 106 is small in the present embodiment of the present invention, the outside of the roll paper 106 does not contact the first roller 142 . More specifically, the roll paper 106 has a diameter of less than about 50 mm. The first and second rollers 142 and 143 can ensure that the roll paper 106 rolls smoothly regardless of the diameter of the roll paper 106 as the size of the roll paper 106 gradually becomes smaller. The first and second rollers 142 and 143 are positioned such that as the diameter of the rolled paper 106 decreases, at least one roller always contacts the outside of the rolled paper 106, and the outside of the rolled paper 106 does not directly contact the side of the operable cover unit 101b. Front panel 141 .

*Roll paper size detection mechanism

A roll paper size detection mechanism (near end detection mechanism) 160 for detecting when the roll paper in the roll paper chamber 121 is reduced to a predetermined size (predetermined diameter) is provided to the right side of the printer chassis 101a as shown in FIG. Plate 127. The roll paper size detection mechanism 160 has a detection lever, described further below, which is pressed against the round end surface of the roll paper 106 which is pressed against the side of the roll paper chamber 121 during paper conveyance. The front panel 141 of the cover unit 101b is operable. The proximal end of the roll paper 106 is detected when the detection lever separates from the round end of the roll paper 106 to the side toward the rear of the printer (away from the outside edge).

As shown in FIGS. 14A to 14C , the roll paper size detection mechanism 160 includes a frame 161 fixed to the right side plate 132 , a frame 161 connected to the frame 161 freely pivoting on support pins 162 and pressed into the roll paper chamber 121 . A detection lever 163 on the round end surface of the roll paper 106 , a compression spring 164 for pushing the detection lever 163 , and a detection switch 165 operated according to the pivoting action of the detection lever 163 .

The detection lever 163 includes a tapered surface 163a formed on the front end, a contact surface 163b formed on the side face pressed against the round end surface of the roll paper, a rocker portion formed on the rear end portion for operating the detection switch 165 163c, and a spring stopper 163d for holding one end of the stage clip 164. The contact surface 163b is tapered so that the width of the detection lever 163 increases toward the front. In other words, the contact surface 163b tapers (tapers) toward the rear of the printer.

The frame 161 includes a support portion 161a bent into a substantially U shape and supports the detection lever 163, and a spring stopper 161b for holding the other end of the compression spring 164 formed by bending one end of the support portion 161a substantially perpendicularly.

Next, the detecting operation of the roll paper size detecting mechanism 160 will be described with reference to FIGS. 15A and 15B . As shown in FIG. 15A , when the outer diameter of the roll paper 106 is large, the contact surface 163b of the detection lever 163 is pressed against the round end surface 116a of the roll paper 106 . The rocker portion 163c of the detection lever 163 contacts the detection switch 165 at this time, and thus it is known that the roll paper size is larger than the predetermined size.

As shown in FIG. 15B, when the diameter of the roll paper 106 becomes smaller, the force of the compression spring 164 causes the detection lever 163 to separate from the outer edge of the round end surface 116a of the roll paper 106 and move toward the rear of the printer (to the outside of the outer edge) , and protrude into the inside of the roll paper chamber 121. As a result, the rocker portion 163c of the detection lever 163 is separated from the detection switch 165 . The detection switch 165 at this time outputs a near-end state detection signal, ie, an electrical signal indicating that the size of the roll paper 106 has been reduced to a predetermined size or less.

Next, the function of the contact surface 163b (the tapered portion toward the rear of the printer) formed on the detection lever 163 will be described.

This embodiment of the present invention has a detecting rod retracting mechanism for retracting the detecting rod 163 to the outside of the roll paper chamber 121 in conjunction with the opening action of the operable cover unit 101b when the operable cover unit 101b is opened. The contact surface 163b serves as a surface to engage the moving plate 167 of the detection lever retraction mechanism.

FIG. 16 shows the detection lever retraction mechanism which will be described below with reference to FIGS. 12 and 16 . The right side plate 127 of the printer chassis 101 a and the side plate 132 b of the operable cover unit 101 b are connected by the moving plate 167 . When the operable cover unit 101b is opened, the moving plate 167 slides forward along the right side plate 127 (indicated by arrow Y in the drawing). With this action, the distal end 167a of the moving plate 167 contacts the contact surface 163b of the push detection lever 163 and pushes the contact surface 163b of the detection lever 163 to the outside of the roll paper chamber 121 . As a result, when the operable cover unit 101b is opened, the detection lever 163 is retracted to the outside of the roll paper chamber 121 .

Therefore, when the operable cover unit 101b is opened, the detection lever 163 does not protrude into the roll paper chamber 121, and the roll paper 106 is easily replaced, or the roll paper 106 is easily removed and inserted.

When the roll paper 106 moves to the back inside the roll paper chamber 121 and the detection lever 163 is separated from the round end surface 116a of the roll paper 106 (so that the detection lever 163 protrudes), the contact surface 163b is used for returning the detection lever 163 to the pressed against position on the round end surface 116a. More specifically, when the roll paper 106 moves from the rear to the front within the roll paper chamber 121 , the contact surface 163 b of the detection lever 163 is smoothly pushed out from the outer edge portion of the roll paper 106 . As a result, the contact surface 163b can contact the round end surface 116a of the roll paper 106 again. This means, for example, that the return of the roll paper 106 to a predetermined position enables continued detection of when the roll paper 106 has been reduced to a predetermined small size even if shock rolls the roll paper 106 back and forth within the roll paper chamber 121 .

The proximal end of the roll paper 106 is detected when the tapered surface 163a separates from the distal end surface 116a of the roll paper 106 . However, since the roll paper 106 can simply move within the roll paper chamber 121, it is preferable to confirm the near-end detection only after the near-end signal is continuously output for a predetermined time (for example, 10 seconds).

As described above, when the operable cover unit 101 b is opened, the detection lever 163 is retracted from the roll paper chamber 121 , and the operable cover unit 101 b is closed so that the detection lever 163 protrudes into the roll paper chamber 121 . In this case, when the operable cover unit 101b is closed, before the roll paper 106 is stored in the roll paper chamber 121, the detection lever 163 protrudes into the roll paper chamber 121, and the roll paper 106 is held between the detection lever 163 and the roll paper chamber 121. Between the operating cover unit 101b.

More specifically, if the operable cover unit 101b is closed when the roll paper 106 has a small diameter (for example, when the outer diameter is about 50 mm) and the roll paper 106 contacts the first roller 142 ( FIG. 3 ), the roll paper 106 Before rolling into the roll paper chamber 121 , the detecting rod 163 protrudes into the roll paper chamber 121 . As a result, the roll paper 106 may become stuck (jammed) between the detection lever 163 and the front plate 141 of the operable cover unit 101b.

However, in this embodiment of the present invention, a tapered surface 163 a rising toward the top of the printer is formed at the front of the detection lever 163 . The slope of the tapered surface 163a is set such that the rolled paper 106 easily passes over the tapered surface 163a if the small-diameter roll 106 is between the tapered surface 163a and the front plate 141 of the operable cover unit 101b.

More specifically, as shown in FIG. 17, when a force F is applied horizontally to the tapered surface 163a by the roll paper 106, the force F is divided into a force Fcosα acting in the slope direction of the tapered surface 163a and a vertical force Fcosα acting on the tapered surface 163a. Force Fsinα on the slope. If μ is the static friction coefficient of the tapered surface 163a, the slope α of the tapered surface 163a is set so that the expression Fcosα>μFsinα is true. In other words, the gradient α is set to an angle <tan ⁻¹ (1/μ), ie α<tan ⁻¹ (1/μ).

When constituted in this way, even before the roll paper 106 is stored in the roll paper chamber 121, the detection lever 163 protrudes into the roll paper chamber 121, so that the roll paper 106 is positioned between the detection lever 163 and the front plate 141 of the operable cover unit 101b. During this time, when the operable cover unit 101b is closed, the rolled paper 106 slides along the upwardly facing tapered surface 163a and is stored in the rolled paper chamber 121.

As described above, the roll paper printer 100 according to this embodiment of the present invention has the detection lever retraction mechanism that moves the detection lever 163 in conjunction with opening and closing the operable cover unit 101b. When the operable cover unit 101b is opened, the detection lever 163 retracts to the outside of the roll paper chamber 121 as the operable cover unit 101b is opened. Therefore, when the operable cover unit 101b is opened, the detection lever 163 of the roll paper size detection mechanism 160 does not protrude into the roll paper chamber 121, and the roll paper 106 is easily replaced, removed, or loaded.

In this embodiment of the invention, the rolled paper 106 is pressed toward the operable cover unit 101b during paper conveyance, and the proximal end of the rolled paper 106 is detected by the detection lever 163 pressed against the round end surface of the rolled paper 106 . As a result, the roll paper 106 can be held so that it does not move to the front of the roll paper chamber 121 without providing a groove in the bottom of the roll paper chamber 121 as required in the prior art. The size of the roll paper printer 100 can thus be reduced by an amount corresponding to the savings obtained by omitting the slot, and the proximal end of the roll paper 106 can be reliably detected.

And, when the detection lever 163 of the roll paper size detection mechanism 160 is pressed against the distal end surface 116a of the roll paper 106 and the roll paper 106 is consumed so that the outer diameter of the roll paper 106 is small, the detection lever 163 faces the printer back and the roll paper The outer edge of the distal end surface 116a of 106 separates and protrudes into the roll compartment 121 . The arrangement of this embodiment of the invention enables detection of the proximal end of the roll paper 106 more easily than an arrangement in which the detection rod is inserted into the center of the core of the roll paper 106 .

In addition, a tapered surface 163a is formed on the front end portion of the detection lever 163, and the slope α of the tapered surface 163a is set so that the rolled paper 106 can be moved between the tapered surface 163a and the operable cover unit 101b. Smoothly moves across the tapered surface 163a and is stored in the roll chamber 121 at an angle. As a result, when the operable cover unit 101b is closed, before the roll paper 106 is stored in the roll paper chamber 121, even if the detection lever 163 protrudes into the roll paper chamber 121 and the roll paper 106 is set between the detection lever 163 and the operable cover Between the units 101b, the roll paper 106 can also pass over the tapered surface 163a of the detection lever 163 and be stored in the roll paper chamber 121. Therefore, the problem of the roll paper 106 being locked between the tapered surface 163a and the operable cover unit 101b can be prevented.

A contact surface 163b tapered toward the rear of the printer is formed on the side of the detection lever 163 so that if the roll paper 106 moves to the rear in the roll paper chamber 121, the detection lever 163 is separated from the distal end surface 116a of the roll paper 106, and The roll paper 106 then moves to the front of the roll paper chamber 121 again, and the detection rod 163 touches the round end surface 116a of the roll paper 106 again. Therefore, even if the rolled paper 106 moves within the rolled paper chamber 121 due to vibration, the rolled paper 106 can return to a predetermined position, and the detection of the proximal end of the rolled paper 106 can continue.

*Modification of roll paper size detection mechanism

Next, changes of the roll paper size detection mechanism 160 will be described with reference to FIGS. 18A and 18B. FIG. 18A is a perspective view seen from the top of the roll paper size detection mechanism 160A, and FIG. 18B is a perspective view of the detection lever 163A. Note that parts having the same or similar functions in the drawings are denoted by the same reference numerals, and thus further descriptions thereof are omitted.

The roll paper size detection mechanism 160A differs from the roll paper size detection mechanism 160 described above in that an inclined guide surface 163e facing the top and inside of the printer is presented (formed) on the top 163f of the detection lever 163A. The guide surface 163e is formed on the side of the vertically extending portion 163g of the tapered surface 163a of the detection rod 163A, and has a slope descending to the contact surface 163b.

As described above, when the operable cover unit 101 is closed, before the roll paper 106 is stored in the roll paper chamber 121 , the detection lever 163 may protrude into the inside of the roll paper chamber 121 . When the operable cover unit 101b is quickly closed, the roll paper 106 may slowly arch upward on the top 163f of the detection lever 163A according to the outer diameter of the roll paper 106 .

Therefore, in the present embodiment, the tapered guide surface 163e is formed on the top 163f. Since the outer peripheral edge of the roll paper 106 touches the tapered guide surface 163e from above, the weight of the roll paper 106 and the corresponding acceleration of gravity make the detection rod 163A smoothly pushed to the outside of the roll paper chamber 121 .

As a result, the rolled paper 106 moves on the rolled paper holder 129 , and the contact surface 163 b touches the round end surface 116 a of the rolled paper 106 . Therefore, when the roll paper 106 is small and the operable cover unit 101b is quickly closed with a force so that the roll paper 106 slowly arches upward onto the detection lever 163A, the detection lever 163A is pushed by the roll paper 106 in contact with the tapered guide surface 163e , and is held against the rounded end surface 116a of the roll paper 106. It is therefore possible to continue detecting the near end of the roll paper.

This aspect of the invention describes forming the tapered guide surface 163e on an extension of the tapered surface 163a, but the tapered guide surface may also be formed on the entire top 163f, or the tapered guide surface may be formed on the top 163f. lead ribs.

The present invention has been described taking a roll paper printer with a thermal head as an example. It will be apparent to those skilled in the art that the invention is also applicable to roll paper printers using other types of print heads, for example including inkjet heads or dot heads.

Although the invention has been described with reference to the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications will be apparent to those skilled in the art. As long as such changes and modifications do not depart from the scope of the present invention, they should be construed as being included in the scope of the present invention as defined by the appended claims.

Claims (13)

1. A roll paper printer, comprising: a roll paper storage unit having a bottom surface on which the roll paper is held and rolled; an operable cover unit for opening and closing a roll paper loading opening to the roll paper storage unit; a roll paper size detection mechanism including a detection lever movable in a direction protruding into the roll paper storage unit and in a direction retracted from the roll paper storage unit, and a pushing member for pushing the detecting rod in the protruding direction, It is characterized in that, when the outer diameter of the rolled paper stored in the rolled paper storage unit is reduced to a predetermined size or less, the detection lever is separated from the rolled paper and pushed in the protruding direction; and a detecting rod retracting mechanism, the detecting rod retracting mechanism is used to cooperate with the opening of the operable cover unit, resist the pushing force of the pushing member, move in the retracting direction and protrude into the roll paper storage unit detection rod. 2. The roll paper printer according to claim 1, wherein: The detecting lever retracting mechanism operates in conjunction with the opening and closing action of the operable cover unit, and includes a movement between a first position separated from the detecting lever and a second position pushing the detecting lever in a retracting direction. Move board. 3. The roll paper printer according to claim 2, wherein: The detecting rod retracting mechanism includes a pushing member for pushing the moving plate toward the first position. 4. The roll paper printer according to claim 1, wherein: The detection lever is pressed against the round end of the roll paper stored in the roll paper storage unit, and when the outer diameter of the roll paper is reduced to a predetermined size or less, the detection lever and the roll paper The round ends are separated and pushed in the protruding direction. 5. The roll paper printer according to claim 4, wherein: The detection lever is pushed in the protruding direction so as to be separated from the inner peripheral edge of the round end of the roll paper and enter into the core hole at the center of the round end of the roll paper. 6. The roll paper printer according to claim 5, wherein: The roll paper storage unit stores the roll paper, and the rotation axis of the roll paper is aligned with the width direction of the printer; The protruding direction and the retracting direction of the detection rod are aligned with the width direction of the printer; the roll paper loading opening is formed on the roll paper storage unit at the front side of the printer; and The operable cover unit is openable toward the front of the printer pivoted about a bottom end portion of the operable cover unit, and has a paper platen defining a printing position of a print head attached to the operable cover unit the top part of. 7. The roll paper printer according to claim 6, wherein: The detecting lever retracting mechanism operates in conjunction with the opening and closing of the operable cover unit, and includes movement in the front-rear direction of the printer between a first position separated from the detecting lever and an advanced position pushing the detecting lever in a retracted direction. mobile board. 8. The roll paper printer according to claim 7, wherein: The detecting lever retracting mechanism includes a pushing member for pushing the moving plate toward the rear of the printer. 9. The roll paper printer according to claim 4, wherein: When the detection lever is separated from the outer circumferential edge of the roll paper, the detection lever is pushed in the protruding direction. 10. The roll paper printer according to claim 9, wherein: The roll paper storage unit stores the roll paper, and the rotation axis of the roll paper is aligned with the width direction of the printer; When the detection rod is separated from the outer peripheral edge of the roll paper, the detection rod is pushed in the protruding direction; a roll paper loading opening is formed on the roll paper storage unit at the front side of the printer; and the operable cover unit is openable toward the front of the printer pivoted about a bottom end portion of the operable cover unit, and has a paper platen defining a printing position of a print head attached to a top end portion of the operable cover unit; and The roll paper stored in the roll paper storage unit is pressed to the operable cover unit while advancing toward the printing position. 11. The roll paper printer according to claim 10, wherein: An upwardly facing tapered surface rising toward the top of the printer is formed at a front end portion of the detection lever facing the operable cover unit; and The slope of the upwardly facing tapered surface is set to push the operable cover unit in the closing direction such that a roll paper disposed between the upwardly facing tapered surface and the operable cover unit can move over the upwardly facing tapered surface to the rear side of the detection rod. 12. The roll paper printer according to claim 10, wherein: forming a rearward-facing tapered surface facing the rear of the printer on the side of the detection lever facing the roll paper storage unit; and The rearwardly facing tapered surface is capable of contacting an outer peripheral edge portion of the end of the web moving from the rear to the front of the detection rod. 13. The roll paper printer according to claim 10, wherein: forming a tapered guide surface facing the inner side in the width direction of the printer at the top of the detection rod; and The tapered guide surface is capable of contacting the outer circumferential edge of the end of the web moving downward from the top of the detection rod.

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