Patent Description:
Printers that issue receipts and the like are used in a wide range of applications such as store registers, automated teller machines and cash dispensers in banks, and so forth. Some of such printers print on recording paper using a print head or the like while transporting the recording paper, and cut the recording paper with a cutter.

There is a printer that has a main body of the printer and a cover that is supported by the main body in a rotatable fashion, and roll-shaped recording paper can be set in the main body by opening the cover. A print head is provided in the main body, and a platen roller is provided in the cover, and, when the cover is closed, the recording paper is sandwiched between the print head and the platen roller. With the recording paper sandwiched between the print head and the platen roller, printing is performed on the recording paper.

A printer that cuts recording paper with a cutter including a movable blade and a fixed blade can cut the recording paper by moving the movable blade towards the fixed blade while the recording paper is sandwiched between the movable blade and the fixed blade. Reference may be made to <CIT> which relates to a printer including a fixed blade and a movable blade that cuts recording paper subjected to printing by a print head, and a movable blade slider including a projecting part provided on a surface of the movable blade slider. The movable blade is provided on the movable blade slider with the projecting part of the movable blade slider entering an opening provided in the movable blade.

A cutter that has repeated cutting recording paper is likely to be damaged. A damaged cutter cannot cut recording paper, and needs to be replaced. However, replacing the movable blade alone is not easy for the user, and is usually done by a specialist by using special tools. Also, a worn cutter needs to be replaced too.

There is a demand for a printer with a movable blade that is easy to replace.

The present invention is defined by the appended independent claim to which reference should now be made. Specific embodiments are defined in the dependent claims. According to one arrangement, a printer configured to cut recording paper with a fixed blade and a movable blade has a blade unit including the movable blade and a slider to which the movable blade is attachable, and the slider includes: a contact part configured to contact the movable blade; a flexible part formed thinner than the contact part; and a first protrusion provided on the flexible part and configured to engage with a first opening provided in the movable blade.

According to another arrangement, a blade unit has a movable blade that cuts recording paper with a fixed blade, the blade unit including the movable blade and a slider to which the movable blade is attachable, and the slider includes: a contact part configured to contact the movable blade; a flexible part formed thinner than the contact part; and a first protrusion provided on the flexible part and configured to engage with a first opening provided in the movable blade.

The present invention makes it possible, with a printer having a cutter, to replace a movable blade with ease.

Hereinafter, a description will be given of the present embodiment of the present invention with reference to the drawings.

In the following description, the X direction will refer to the longitudinal direction of the movable blade according to the present embodiment. The Y direction will refer to the lateral direction of the movable blade. The Z direction will refer to the direction that is orthogonal to both the X axis and the Y axis.

The direction in which the arrow points along the X direction will be referred to as the "+X direction," and its opposite direction will be referred to as the "-X direction. " The direction in which the arrow points along the Y direction will be referred to as the "+Y direction," and its opposite direction will be referred to as the "-Y direction. " The direction in which the arrow points along the Z direction will be referred to as the "+Z direction," and its opposite direction will be referred to as the "-Z direction. " The X direction corresponds to the left-right direction.

<FIG> is a cross-sectional view of a printer <NUM> according to the present embodiment, and <FIG> is a perspective view of the printer <NUM>. The printer <NUM> includes
a print head <NUM>, such as a print head that prints on recording paper P, which is thermal paper or the like, a platen roller <NUM> that transports the recording paper P, and a movable blade <NUM> and a fixed blade <NUM> that cut the recording paper P.

The printer <NUM> includes a printer main body (hereinafter "main body") <NUM>, and a blade unit <NUM> that can be attached to and removed from the main body <NUM>. The main body <NUM> is attached to a housing (not shown), and the blade unit <NUM> is attached to a cover <NUM> in a removable fashion, where the cover <NUM> is attached to the housing in a rotatable fashion. By opening the cover <NUM>, it is possible to remove the blade unit <NUM> from the main body <NUM>, and set the recording paper P between the main body <NUM> and the blade unit <NUM>. Closing the cover <NUM> places the recording paper P in a state ready for printing using the print head <NUM>. Note that <FIG> shows a state in which the cover <NUM> is closed, while <FIG> shows a state in which the blade unit <NUM> is removed from the main body <NUM>.

The print head <NUM> and the fixed blade <NUM> are set in the main body <NUM>, and the platen roller <NUM>, the movable blade <NUM>, and the slider <NUM> are provided in the blade unit <NUM>.

The movable blade <NUM> and the fixed blade <NUM> in <FIG> constitute a cutter. The movable blade <NUM> moves in the -Y direction with the slider <NUM>.

The fixed blade <NUM> is provided over the spring <NUM>, and is preloaded by the spring <NUM> in the +Z direction, towards the movable blade <NUM>.

The recording paper P is cut as the movable blade <NUM> passes over the fixed blade <NUM>. A recording paper guide <NUM> that forms the transport path and guides the recording paper is set on the printing surface side, upstream of the print head <NUM> of the transport path of the recording paper P. A heat sink <NUM> for discharging the heat generated in the print head <NUM> is provided on the rear surface of the print head <NUM>.

<FIG> is an exploded view of the blade unit <NUM>. The blade unit <NUM> includes the movable blade <NUM>, the slider <NUM>, a frame <NUM>, the platen roller <NUM>, a reinforcing metal fitting <NUM>, and a mounting plate <NUM>.

The movable blade <NUM> is made of a material such as metal, and the blade portion is formed V-shaped. Furthermore, second openings <NUM> are provided near both ends of the movable blade <NUM>, and first openings <NUM> are provided nearer the center than both end parts.

The second openings <NUM> are throughholes having a substantially rectangular shape in plan view, and the first openings <NUM> are throughholes having a substantially circular shape in plan view. However, the shape of each opening is by no means limited to the above, and the second openings <NUM> and the first openings <NUM> may be both throughholes having a substantially circular shape or a substantially rectangular shape, or throughholes having a substantially elliptical shape or a long hole shape in plan view.

A notch <NUM> is provided on the opposite side of the movable blade <NUM>, near the center of the blade. At least part of the movable blade <NUM> is formed asymmetrical by the notch <NUM>.

With this printer, the movable blade <NUM> and the fixed blade <NUM> may be slightly curved longitudinally so that their convex sides face each other, in order to reduce the contact area between the movable blade <NUM> and the fixed blade <NUM> for improved cutting performance. There is a concern that, if the front and the back of the movable blade <NUM> are mistaken when assembling the movable blade <NUM> onto the slider <NUM>, the convex sides of the movable blade <NUM> and the fixed blade <NUM> might not face each other, and the cutter's cutting performance might decrease. By forming the movable blade <NUM> at least partially asymmetrical, it is possible to prevent the front and the back of the movable blade <NUM> from being misassembled onto the slider <NUM>, and preventing the cutter's cutting performance from decreasing.

The slider <NUM> is made of a resin material or the like. Racks <NUM> are provided on both left and right sides on the -Z surface of the slider <NUM>, and connected with pinions (not shown) that are connected to the motor that drives the movable blade via a gear or the like. When the motor rotates, the pinions rotate, and this rotation is transmitted to the racks <NUM> and allows the slider <NUM> to move in the Y direction.

By moving the slider <NUM>, assembled with the movable blade <NUM>, the movable blade <NUM> can be moved. The movable blade <NUM> and the slider <NUM> are attached to the +Z side of the frame <NUM>, so as to sandwich the movable blade <NUM> between the slider <NUM> and the frame <NUM>. Furthermore, the metal fitting <NUM> and the plate <NUM> are mounted so as to cover the movable blade <NUM> and the slider <NUM>. The metal fitting <NUM> and the plate <NUM> are made of metal or the like. Furthermore, the platen roller <NUM> is attached to the frame <NUM> in a rotatable fashion. Note that <FIG> omits the illustration of the metal fitting <NUM>.

<FIG> are diagrams that show examples of the slider <NUM>. <FIG> is a perspective view seen from the -Z side, <FIG> is a partially enlarged view of the region A of <FIG> is a cross-sectional view taken along cutting line B-B in <FIG>.

In the slider <NUM> shown in <FIG>, second protrusions <NUM>, holes <NUM>, flexible parts <NUM>, first protrusions <NUM>, accommodating parts <NUM>, and guide parts <NUM> are provided.

The second protrusions <NUM> are provided near both end parts on the -Z surface of the slider <NUM>, and are protrusions having a substantially rectangular shape in plan view.

The second protrusions <NUM> are formed in a substantially rectangular shape, in which the lengths of the long side and the short side are equal to the shape of the pair of second openings <NUM> of the movable blade <NUM>, or formed in a substantially rectangular shape in which the lengths of the long side and the short side are slightly smaller. Formed in this shape, when the movable blade <NUM> is attached to the slider <NUM>, the pair of second protrusions <NUM> can engage with the second openings <NUM> with ease. Furthermore, when removing the movable blade <NUM> from the slider <NUM>, the second protrusions <NUM> can be pulled out of the second openings <NUM> with ease.

In the second protrusions <NUM> shown in <FIG>, a first inclined part 321a is formed. The first inclined part 321a is inclined by an angle θ1 so that the -Y side is higher and the +Y side is lower.

The holes <NUM> are provided nearer the center than both end parts of the slider <NUM>. The holes <NUM> of <FIG> are throughholes that are provided so as not to come into contact with the movable blade <NUM>. In each hole <NUM>, a flexible part <NUM> with a beam hung over the hole <NUM> is provided. On the -Z surface of each flexible part <NUM>, a first protrusion <NUM>, having a substantially circular shape in plan view, is provided.

The first protrusions <NUM> are formed in a substantially circular shape that is substantially equal to the shape of the pair of first openings <NUM>, or formed in a substantially circular shape with a slightly smaller diameter. Formed in such a shape, the pair of second protrusions <NUM> can engage with the second opening <NUM> with ease when the movable blade <NUM> is attached to the slider <NUM>. Furthermore, when removing the movable blade <NUM> from the slider <NUM>, the second protrusions <NUM> can be pulled out of the second openings <NUM> with ease.

In the first protrusion <NUM> shown in <FIG>, a second inclined part 324a is provided. The second inclined part 324a is inclined by an inclination θ2 so that the +Y side is higher and the -Y side is lower.

The movable blade <NUM> attached to the slider <NUM> is in contact with the contact part <NUM>. The thickness t1 of the flexible part <NUM> is formed thinner than the thickness t0 of the slider <NUM> in the contact part <NUM>, so that the flexible part <NUM> is easier to flex than the contact part <NUM>.

To ensure the mechanical strength of the flexible part <NUM>, it is preferable to make the thickness t1 of the flexible part <NUM> thick. On the other hand, to ensure the flexibility of the flexible part <NUM>, which is required when attaching or removing the movable blade <NUM> to or from the slider <NUM>, it is preferable to make the thickness t1 thin. For example, when the thickness t0 of the contact part <NUM> is <NUM>, the thickness t1 of the flexible part <NUM> is made, for example, <NUM> or more, and <NUM> or less.

By making the beam hung over the hole <NUM> the flexible part <NUM>, the flexible part <NUM> flexes more easily. The narrower the width of the beam, the more easily the flexible part <NUM> flexes, and therefore, for example, the beam's width may be made substantially equal to the width of the first protrusion <NUM> in the Y direction.

In the outer periphery of each hole <NUM>, an accommodating part <NUM> is provided so that part of the movable blade <NUM> mounted on the -Z side of the slider <NUM> can be accommodated. Each accommodating part <NUM> is formed in a box shape, and its wall parts corresponding to the inward X direction and the -Y direction are open.

Each accommodating part <NUM> has an abutting surface <NUM>, to which, when the movable blade <NUM> is attached to the slider, the surface of the movable blade opposite to the surface facing the slider <NUM> is abutted. The accommodating part <NUM> accommodates the movable blade <NUM> inside, using its open-wall parts, so that the -Z surface of the movable blade <NUM> can be abutted against the abutting surface <NUM>.

The guide parts <NUM> are provided in the outward X direction of each accommodating part <NUM>, and are long holes with their longitudinal direction oriented in the Y direction. By inserting projection parts <NUM>, which are provided in the frame <NUM>, into the guide parts <NUM>, the move of the movable blade <NUM> and the slider <NUM> in the Y direction with respect to the frame <NUM> can be guided.

Note that, although <FIG> each show a structure in which the flexible parts <NUM> are beams hung over the holes <NUM>, which are throughholes, this is by no means limiting. <FIG> are diagrams that each show another example of the slider <NUM>, where <FIG> is a perspective view seen from the -Z side, <FIG> is a partially enlarged perspective view of the region C of <FIG> is a cross-sectional view taken along cutting line D-D in <FIG>.

As shown in <FIG>, recess parts, which are modified examples of the holes <NUM>, are formed on the +Z surface and the -Z surface of the slider <NUM>. Hereinafter, such recess parts will be also treated as "holes. " The recess parts are thinner in thickness than the contact parts <NUM>, and these parts serve as the flexible parts <NUM>. The recesses are formed on both surfaces of the slider <NUM>, so that it is possible to prevent the flexible parts <NUM> from coming into contact with the movable blade <NUM>.

The attachment and removal of the movable blade <NUM> to and from the slider <NUM> in the blade unit <NUM> will be described below. <FIG> are perspectives view that show the move of the movable blade <NUM> and the slider <NUM> when the slider <NUM> is attached to or removed from the movable blade <NUM>. <FIG> is a perspective view showing a state before the slider <NUM> is moved, and <FIG> is a perspective view showing a state after the slider <NUM> is moved. <FIG> provide perspective views of the blade unit seen from the rear side, each showing a state in which the metal fitting <NUM> and the plate <NUM> are removed.

<FIG> provide diagrams showing attachment of the movable blade <NUM> to the slider <NUM>. <FIG> is a diagram showing a state in which the movable blade <NUM> is being attached, <FIG> is a cross-sectional view taken along cutting line E-E in <FIG> is a diagram showing a state after the movable blade <NUM> is mounted, and <FIG> is a cross-sectional view taken along cutting line F-F in <FIG>.

<FIG> provide diagrams showing removal of the movable blade <NUM> from the slider <NUM>. <FIG> is a diagram showing a state in which the movable blade <NUM> is being removed, <FIG> is a cross-sectional view taken along cutting line G-G in <FIG> is a diagram showing a state in which the movable blade <NUM> is ready for removal.

Referring to <FIG>, the frame <NUM> is provided with a gear <NUM> for driving the movable blade. The gear <NUM> is driven by a motor provided in the main body <NUM>, and meshes with an intermediate gear (not shown) provided inside the blade unit <NUM>. The intermediate gear meshes with the racks <NUM> provided in the slider <NUM>. The movable blade <NUM> and the slider <NUM> move in the -Y direction in conjunction with the rotation of the gear <NUM>, thereby cutting the recording paper P.

When the gear <NUM> rotates in the direction of the arrow <NUM> with the cover <NUM> open, the movable blade <NUM> and the slider <NUM> move in the -Y direction via the intermediate gear. By this means, as shown in <FIG>, the slider <NUM>, with the movable blade <NUM> attached, comes out of the blade unit <NUM>, and the first protrusions <NUM> become visible, so that, after the movable blade <NUM> and the slider <NUM> are put to a stop, the movable blade <NUM> can be attached to or removed from the slider <NUM>.

As shown in <FIG>, the frame <NUM> is provided with projection parts <NUM> to be inserted into the guide parts <NUM>. When the gear <NUM> is rotated to move the movable blade <NUM> and the slider <NUM>, the guide parts <NUM> can allow the movable blade <NUM> and the slider <NUM> to move smoothly in the Y direction, and, furthermore, limit the range of their movement. Furthermore, by mounting the metal fitting <NUM> on the +Z side of the slider <NUM>, it is possible to prevent the movable blade <NUM> and the slider <NUM> from coming off the frame <NUM>.

When attaching the movable blade <NUM> to the slider <NUM>, as shown in <FIG>, the movable blade <NUM> is arranged slightly on the -Y side of the slider <NUM> so as to make the +Z surface of the movable blade <NUM> and the -Z surface of the slider <NUM> face each other. In this state, as shown in <FIG>, the first protrusions <NUM> are pushed by the +Z surface of the movable blade <NUM>, and the flexible parts <NUM> flex towards the +Z side.

Subsequently, the movable blade <NUM> is moved in the +Y direction. When the first openings <NUM> reach the position where the first openings <NUM> and the first protrusions <NUM> overlap in plan view, as shown in <FIG>, the flexible parts <NUM> flex back, and each first opening <NUM> enters the first protrusion <NUM>. As a result of this, the movable blade <NUM> is fixed to the slider <NUM>.

Since the second inclined parts 324a are inclined by an angle θ2 so as to make +Y side higher, compared to the case without an inclination, the movable blade <NUM> can move in the +Y direction with ease, and the first openings <NUM> can enter the first protrusions <NUM> with ease. Furthermore, the movable blade <NUM> attached to the slider <NUM> can be fixed reliably.

After the movable blade <NUM> is moved in the +Y direction and the first openings <NUM> reach the position where the first openings <NUM> and the first protrusions <NUM> overlap in plan view, the first protrusions <NUM> are inserted into the first openings <NUM>. As a result of this, the movable blade <NUM> can be positioned in the X direction and in the Y direction, with ease, with respect to the slider <NUM>, that is, in the in-plane direction of the movable blade <NUM>.

The movable blade <NUM> is moved in the +Y direction, and part of the movable blade <NUM> is accommodated in the accommodating parts <NUM>. By doing so, the -Z surface of the movable blade <NUM> is abutted against the abutting surfaces <NUM>, so that the movable blade <NUM> can be positioned in the Z direction as well, with ease, with respect to the slider <NUM>, that is, in the out-of-plane direction of the movable blade <NUM>.

By inserting the first protrusions <NUM> into the first openings <NUM>, the movable blade <NUM> is positioned in the XY plane, with respect to the slider <NUM>. Furthermore, by inserting the second protrusions <NUM> into the second openings <NUM>, the second protrusions <NUM> are allowed to serve as stoppers, so that, when the movable blade <NUM> moves and cuts paper, the movable blade <NUM> does not drift by being pushed by the paper. Furthermore, by accommodating part of the movable blade <NUM> in the accommodating parts <NUM>, the movable blade <NUM> is positioned in the Z direction with respect to the slider <NUM>. In this way, the positioning function per direction and the stopper function are shared by each structure.

With the present embodiment, the first opening <NUM> on the +X side is a long hole whose longitudinal direction is aligned with the X direction. This is to avoid the case where two first openings <NUM> are made openings of the same circular shape and where the two first protrusions <NUM> cannot be inserted in the respective first openings <NUM> smoothly due to a manufacturing error or the like. However, it is not necessary to make one of the first openings <NUM> a long hole, and both may be formed in a substantially circular shape or the like.

When removing the movable blade <NUM> from the slider <NUM>, as shown in <FIG>, pushing the first protrusions <NUM> engaged with the first openings <NUM> towards the +Z side makes the flexible parts <NUM> flex in the direction pushed, and the first protrusions <NUM> slip out of the first openings <NUM>. This sets the movable blade <NUM> ready for removal from the slider <NUM>. In this state, by pulling the second protrusions <NUM> out of the second openings <NUM> and moving the movable blade <NUM> towards the -Y side, the movable blade <NUM> can be removed from the slider <NUM>, as shown in <FIG>.

The first inclined part 321a is inclined by angle θ1, which makes the -Y side higher, so that, compared to the case without an inclination, the movable blade <NUM> can move in the -Y direction with ease, and the second protrusions <NUM> can be pulled out of the second openings <NUM> more easily. In addition, the movable blade <NUM> attached to the slider <NUM> can be fixed reliably.

When the cover is closed, the movable blade <NUM> is pushed against the slider <NUM> side by the spring <NUM> that pushes the fixed blade <NUM> upward. Therefore, even if the movable blade <NUM> moves and exits from the blade unit, the second openings <NUM> do not come off the second protrusions <NUM>, nor do the first openings <NUM> come off the first protrusions <NUM>. Therefore, even when the recording paper P is cut by the movable blade <NUM> and the fixed blade <NUM>, the movable blade <NUM> does not come off.

As described above, according to the present embodiment, a slider <NUM> includes contact parts <NUM> that are in contact with a movable blade <NUM>, flexible parts <NUM> that are formed thinner than the contact parts <NUM>, and first protrusions <NUM> that are provided on the flexible parts <NUM>. The movable blade <NUM> has first openings <NUM>, and first openings <NUM> of the movable blade <NUM> engage with the first protrusions <NUM>.

This structure makes it possible to fix the movable blade <NUM> to the slider <NUM> reliably, and to form the first protrusions <NUM> easy to engage with the first openings <NUM>. Compared to the method of mounting the movable blade on the slider by applying pressure to openings and fitting them into protrusions, or the method of fixing the movable blade and slider to a frame, the movable blade <NUM> can be attached to the slider <NUM> with ease. Furthermore, the movable blade <NUM> can be removed from the slider <NUM> with ease. Therefore, the user can replace the movable blade and/or the like by himself/herself.

Furthermore, the printer <NUM> includes a main body <NUM>, and a cover <NUM> that is joined with the main body <NUM> such that the cover <NUM> can be opened and closed. a fixed blade <NUM> is set in the main body <NUM>, and a blade unit <NUM> is set in the cover <NUM>. Then, with the cover <NUM> open, the movable blade <NUM> can be attached to and removed from a slider <NUM> with ease.

Furthermore, the slider <NUM> is provided with flexible parts <NUM>, and the flexible parts <NUM> are provided with first protrusions <NUM>. When the movable blade <NUM> is attached to and removed from the slider <NUM>, the first protrusions <NUM> are pushed, and the flexible parts <NUM> flex partly.

If the whole slider is configured to flex when the movable blade is attached to and removed from the slider, the movable blade also flexes following the flex of the slider, and stress might be applied to the movable blade. However, by allowing the slider to flex partly in the flexible parts <NUM>, it is possible to prevent such stress from being produced. In particular, when the movable blade is curved slightly for improved cutting performance, there is a concern that the way the movable blade is curved might change due to stress, so that the advantage of providing the flexible parts <NUM> becomes more obvious.

Claim 1:
A blade unit (<NUM>) comprising a movable blade (<NUM>) that cuts recording paper with a fixed blade (<NUM>), the blade unit (<NUM>) including a slider (<NUM>) to which the movable blade (<NUM>) is attachable, wherein the slider (<NUM>) includes:
a contact part (<NUM>) configured to contact the movable blade (<NUM>); and it is further characterized by comprising
a flexible part (<NUM>); and
a first protrusion (<NUM>) provided on the flexible part (<NUM>) and configured to engage with a first opening (<NUM>) provided in the movable blade (<NUM>) ;
wherein the flexible part (<NUM>) is formed thinner than the contact part (<NUM>) such that the flexible part (<NUM>) flexes in a direction in which the first protrusion (<NUM>) is pushed.