Platen unit, and printer equipped with platen unit

Abstract

To prevent defective printing, deterioration in printing quality, and damages to a printer head that can occur when carrying out printing while conveying a printing object, such as a consumable, in a state of holding the printing object between a platen unit and the printer head.SOLUTION: A platen unit 10 attached to a printer 100 comprises: a shaft 11 which is disposed at a position opposing a printer head 60 printing on a consumable S being a printing object and composed of an elastic member, and which conveys the consumable S by rotating in a state of holding the consumable S between the platen unit and the printer head 60; and first guides 12 that are provided on both sides of a contact surface 10S of the shaft 11 and that define an annular concavity C1 and provide guidance from the side when the consumable S is conveyed. Further, the shaft 11 is made of a metallic material, and the first guides 12 are made of a high polymeric material.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to a platen unit and a printer including the platen unit. [Background technology]

[0002] Conventionally, printers have been developed for directly printing terminal numbers and symbols used in electrical equipment on consumables such as tubular members called resin tubes and sleeves, and sheet-like members such as plates and tapes. As an example of such a printer, the present applicant has proposed in Patent Document 1 a device configured to convey tubular members sandwiched between a printer head (thermal head) and a platen roller, and flatten the tubes and perform printing. Patent Document 2 also discloses a thermal printer in which a platen roller is provided with a guide groove for guiding a print medium. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-245656 [Patent Document 2] Japanese Patent Application Publication No. 5-330105 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional printers that handle consumables, a rubber-based material that has the elasticity to press the consumables appropriately against the printer head and the frictional force required for transport (e.g., the elastic member in Patent Document 1) tends to be selected as the outer surface material of the platen roller that transports the consumables in close planar contact with the printer head. Also, even in printers that use general paper or sheets, the platen roller is often made of an elastic rubber-based material to prevent damage to the printer head due to contact with the platen roller, for example.

[0005] Under these circumstances, the present applicant has been working to further improve consumable printers and has been diligently studying the structure of the platen mechanism, including the diversity and versatility of printing patterns on consumables. As a result, it has been discovered that depending on the material and shape of the consumables, poor printing or deterioration of print quality may be a concern. Specifically, when both consumables are made of a resin consumable and a rubber platen roller, and both have a certain degree of elasticity, such as when the movement of the shaft that applies the conveying force does not match the movement of the platen roller and the consumable, which may result in a situation where the desired printing cannot be achieved on the intended part of the consumable.

[0006] More specifically, in conventional consumable printers, a cutter is provided downstream in the consumable's transport direction, and performs a partial or full cut of the consumable after printing (see, for example, paragraph 0024 of Patent Document 1). The consumable is transported and printed while repeatedly stopping and moving intermittently. If both the consumable and the platen roller are elastic, the platen roller first bends to follow the rotation of the shaft, which is the main rotating element, and then the consumable bends to follow the platen roller. As a result, printing is performed while the consumable is transported in this bent state. When the rotation of the shaft stops at any time to cut the consumable downstream, the platen roller and, by extension, the consumable, deform and stop slightly later, trying to eliminate the bend. This can easily lead to printing defects, such as white streaks (where a portion of the print is left unprinted).

[0007] On the other hand, when the shaft starts moving again after stopping, the platen roller and therefore the consumables start moving slightly later than the movement of the shaft, so this time the print area becomes distorted and compressed, making it difficult to obtain the intended print state.It was also found that these phenomena can be particularly noticeable in types where the consumables are sandwiched vertically between the printer head and platen roller, as opposed to types where the consumables are sandwiched in a plane, such as the printer described in Patent Document 1.

[0008] Furthermore, in printers such as those described in Patent Document 2, there is a possibility that the printer head may come into direct contact with the surface of the guide groove (the surface between the guides provided on both ends of the platen roller), and if a non-elastic material such as metal is used in that area, there is a risk that the printer head may be damaged.

[0009] Therefore, the present disclosure aims to provide a platen unit that can prevent poor printing or deterioration in print quality when printing on a printing target such as a consumable item while it is being transported while being clamped between the platen roller and the printer head, and can prevent damage to the printer head due to contact between the platen roller and the printer head, and a printer equipped with the platen unit. [Means for solving the problem]

[0010] To solve the above problems, one example of a platen unit according to the present disclosure includes a shaft that is disposed opposite a printer head that prints on a print target such as a consumable made of an elastic material, and that transports the print target by rotating while sandwiching the print target between itself and the printer head, and first guides that are provided on both sides of a contact surface of the shaft that comes into contact with the print target, and that define annular recesses together with the contact surfaces to guide the print target from the sides as it is transported. The shaft is made of a metal material, and the first guides are made of a polymeric material.

[0011] In this configuration, the target to be printed is conveyed while in contact with the shaft made of metal, so the movement of the shaft and the movement of the target to be printed match, preventing the target from being distorted during conveyance. As a result, even if the shaft rotation is repeatedly stopped and started to cut the target to be printed, bending and distortion of the target to be printed are effectively suppressed. In addition, the first guide prevents the printer head from directly contacting the shaft, and because the first guide is made of a polymer material (relatively softer than the shaft), even if the printer head does come into contact with the first guide, the impact is mitigated. [Effects of the Invention]

[0012] With the platen unit and printer disclosed herein, even if the shaft repeatedly stops and starts, the movement of the printing target follows the rotation of the shaft, preventing bending or distortion. This effectively prevents misalignment of the printing position, resulting in poor printing and poor print quality. Furthermore, because the first guide is made of a polymeric material, even if the printer head comes into contact with the first guide, the impact is absorbed, minimizing damage to the printer head. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a perspective view showing an example of the external configuration of a printer according to an embodiment of the present invention, showing the printer as viewed from slightly left side when facing the front of the printer. FIG. [Figure 2] 1 is a perspective view showing an example of the external configuration of a printer according to an embodiment of the present invention, showing the printer as viewed from slightly left side facing the rear of the printer. FIG. [Figure 3] FIG. 10 is a perspective view showing the printer with the cover open and consumables set in the printer, viewed from above at a slight angle toward the front. [Figure 4] 4 is a front cross-sectional view taken along line IV-IV in FIG. 3 with the cover closed. [Figure 5] FIG. 4 is an enlarged perspective view of the platen unit and its surroundings of the printer in the state shown in FIG. 3. [Figure 6] FIG. 2 is a perspective view showing an example of the main configuration of a platen unit alone. [Figure 7] FIG. 2 is a top view of the platen unit. [Figure 8] FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. [Figure 9] 1 is a front cross-sectional view showing a state in which a cylindrical member having a generally rectangular cross section as a consumable item is set in a printer and is being transported and printed. [Figure 10]FIG. 9 is a cross-sectional view similar to FIG. 8, illustrating a state in which consumables are set on the platen unit. [Figure 11] 9 is a cross-sectional view similar to FIG. 8, illustrating a state in which the consumables set on the platen unit are pressed and crushed by the printer head. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present embodiment will be described below with reference to the accompanying drawings. To facilitate understanding of the description, identical components in each drawing will be assigned the same reference numerals whenever possible, and redundant description will be omitted. However, the embodiments described below are merely examples, and are not intended to exclude various modifications or technological applications not explicitly stated below. In other words, one example of the present disclosure can be implemented with various modifications within the scope of its spirit. Furthermore, the drawings are schematic and do not necessarily correspond to actual dimensions, ratios, etc. Furthermore, parts in the drawings may have different dimensional relationships or ratios. Needless to say, the embodiments described below are only some of the embodiments of the present disclosure, and do not represent all embodiments. Furthermore, other embodiments that can be obtained by those skilled in the art based on the embodiments of the present disclosure without requiring creative acts are all within the scope of protection of the present disclosure.

[0015] <Printer exterior configuration example> 1 and 2 are perspective views showing an example of the exterior configuration of a printer according to this embodiment. FIG. 1 shows the printer 100 viewed from slightly to the left as one faces the front, and FIG. 2 shows the printer 100 viewed from slightly to the left as one faces the rear. As shown in these figures, the printer 100 includes a main body 1 and a lid 2 attached to the top of the main body 1 so as to be able to open and close. The main body 1 and the lid 2 are both housings, e.g., roughly rectangular parallelepipeds, with boundaries formed between them at their front faces 1F, 2F and rear faces 1B, 2B. The main body 1 and the lid 2 are connected at the boundary between their right side faces 1SR, 2SR, and the left side face 2SL of the lid 2 pivots about this boundary, allowing the lid 2 to open and close.

[0016] The front surface 1F of the main body 1 is provided with an input / output display unit 3 for performing various input operations and displaying output to the printer 100, and an operation button 4 for fully cutting a consumable S (an example of a "printing target"), which will be described later. The rear surface 1B of the main body 1 is provided with a connector unit 5 including a power switch and ports for connecting a power cable and other communication cables. The right side surface 1SR and left side surface 1SL of the main body 1 are provided with an insertion opening SI and an ejection opening SO for the consumable S, which will be described later. The left side surface 2SL of the cover 2 is provided with an operation unit 6 for opening and closing the cover 2. The input / output display unit 3 is configured to accept user inputs (e.g., characters and numbers to be printed on the consumable, a request to select the type of consumable, etc.) and output notifications to the user using a plurality of operation buttons, such as character buttons, number buttons, and a print start button, and various displays displayed on a screen such as a liquid crystal display or an organic electroluminescence (EL) display.

[0017] <Printer internal configuration example> Next, Fig. 3 is a perspective view showing the printer 100 with the cover 2 open and viewed from above at a slight angle toward the front, showing the state in which consumables S are set. Fig. 4 is a front cross-sectional view taken along line IV-IV in Fig. 3 with the cover 2 closed.

[0018] As described above, the cover 2 is opened and closed by operating the operation unit 6 (for example, by pulling up a biased handle or button). Specifically, the cover 2 is closed when the locking claw E2 of the cover 2 engages with the locking receptacle E1 of the main body 1 shown in Fig. 3, and the cover 2 can be opened by operating the operation unit 6 to release the engagement. Also, as shown in Fig. 3, the interior of the printer 100 mainly contains the platen unit 10, positioning guide 20, feed amount detection unit 30, and cutting unit 40, which are provided on the main body 1 side, and the ink ribbon unit 50 and printer head 60, which are provided on the cover 2 side.

[0019] The platen unit 10 is an elastic member made of various polymeric materials such as resin or elastomer, and is rotatably and detachably supported by a bearing J provided downstream in the forward transport direction (direction from the right side surface 1SR to the left side surface 1SL of the main body 1) of the consumables S. The platen unit 10 is an elastic member made of various polymeric materials such as resin or elastomer. In this state, the platen unit 10 is driven to rotate (forward or reverse) via a platen gear PG by a transport motor (not shown). As a result, the consumables S are transported in the forward transport direction during normal transport, and, as necessary, the consumables S are transported in the reverse transport direction (direction from the left side surface 1SL to the right side surface 1SR of the main body 1) during reverse transport. Details of the platen unit 10 will be described later.

[0020] The positioning guide 20 is provided along the conveyance direction of the consumables S and has two different types of guides 21 and 22 that guide and support the consumables S so as to position them from both sides. These guides 21 and 22 are arranged on the upstream and downstream sides, respectively, in the forward conveyance direction of the consumables S. The feed amount detection unit 30 is a component that enables printing on different types of consumables S along the same conveyance path, and has a feed amount detection roller 31 for detecting the feed amount (movement amount) when the consumables S are in sheet form, for example. In this embodiment, when printing on a cylindrical member as the consumables S, the feed amount detection roller 31 is not used, and therefore the feed amount detection unit 30 is stored in the lower part of the main body 1 so as to be retracted from the conveyance path of the consumables S (FIGS. 3 and 4 show this state).

[0021] The cutting unit 40 is provided downstream of the platen unit 10 and the printer head 60 in the forward transport direction of the consumables S, and has a half cutter 41 and its receiving base 42 for half-cutting the upper surface of the consumables S, and a pair of full cutters 43, 43 arranged further downstream thereof for full-cutting the consumables S. Of these, the half cutter 41 is configured to move toward and away from the receiving base 42 by a half cutter drive unit (not shown), and the full cutters 43, 43 are configured to move toward and away from each other.

[0022] The ink ribbon unit 50 includes the ink ribbon R, a bobbin 51 that is detachably attached to both sides of the printer head 60 and that houses the ink ribbon R in a wound state, and a cassette 52. The ink ribbon unit 50 is configured so that, when the consumables S are conveyed in the forward direction, the ink ribbon R is fed from the feed reel 51r of the bobbin 51 and collected by the take-up reel 52r of the cassette 52, for example, by an appropriate rotary motor (not shown) that rotates the cassette 52.

[0023] The printer head 60 is disposed opposite the platen unit 10, and applies recording energy supplied from a head drive circuit (not shown) to the ink ribbon R to print predetermined characters, symbols, designs, etc. on the printing surface of the consumable S. The printer head 60 is moved toward or away from the platen unit 10 by an appropriate head movement mechanism (not shown). The printer head 60 is pressed against the platen unit 10 with a predetermined pressure by a head pressing mechanism 61, and is configured to abut against the platen unit 10 via the ink ribbon R, when transporting and printing on the consumable S in the forward transport direction.

[0024] <Platen unit configuration example> Next, an example of the configuration of the platen unit 10 will be described. Fig. 5 is an enlarged perspective view of the platen unit 10 and its surroundings of the printer 100 in the state shown in Fig. 3. Fig. 6 is a perspective view showing an example of the main configuration of the platen unit 10 alone, Fig. 7 is a top view thereof, and Fig. 8 is a cross-sectional view taken along line VIII-VIII in Fig. 7.

[0025] The platen unit 10 includes a shaft 11 that is, for example, generally columnar or cylindrical overall, and a pair of cylindrical first guides 12, 12 fitted onto the shaft 11 so as to cover a portion of the outer circumferential surface of the central portion of the shaft 11. The shaft 11 is a member capable of transmitting power generated by its own rotation to the consumable S, which is the printing target. The central portion of the shaft 11 has multiple sections with different diameters that are larger than the end portions, and the end portions have multiple sections with different diameters that are smaller than the central portion. The first guides 12, 12 are disposed on both sides of a contact surface 10S of the shaft 11 that the consumable S contacts. This configuration defines an annular recess C1 having a bottom surface defined by the contact surface 10S and an inner surface defined by the first guides 12, 12, and the first guides 12, 12 contact the sides of the consumable S as the consumable S is transported.

[0026] The driving platen gear PG described above is attached to one end of the shaft 11, and a bearing 13, a first shaft bush 14, and a second shaft bush 15 are provided on the outer circumferential surface of the shaft 11 between the one end and the center. The bearing 13 is attached to the other end of the shaft 11, and a second shaft bush 15 is provided on the outer circumferential surface of the shaft 11 between the other end and the center.

[0027] Furthermore, a second guide 16 having a recess C2 defined so as to communicate with the annular recess C1 is disposed on the upstream side of the shaft 11 and is held by a pair of holder guides 17. The holder guides 17 are attached to the outer circumferential surfaces of the second shaft bushes 15 at the step between the large diameter and small diameter portions of the shaft 11. This allows the second guide 16 to be rotatably supported on the shaft 11. Furthermore, a guide stopper 18 for fixing the second guide 16 and the holder guide 17 is provided so as to cover the outer circumferential surface of the second shaft bush 15 at the other end of the shaft 11. In this configuration, the second guide 16 is placed from above on an adapter base 1D installed on the main body 1, so that the platen unit 10 is supported and fixed not only at both ends of the shaft 11 but also from below the center. Furthermore, the second guide 16 abuts against the adapter base 1D, restricting rotation.

[0028] In this embodiment, the friction coefficient μ1 of the contact surface 10S of the shaft 11 that contacts the consumable S is set to be larger than the friction coefficient μ2 of the material surface of a portion of the shaft 11 different from the contact surface 10S. One example of a method for relatively increasing the friction coefficient μ1 of the contact surface 10S is to form the contact surface 10S by roughening the material surface of the shaft 11. Among various roughening treatments, the method of applying a foreign substance (ceramic powder, abrasive grains, adhesive, etc.) to the material surface of the shaft 11 is preferable because it is not only simple in terms of the process procedure and the work itself, but also because it facilitates more effective roughening. More specifically, an example of such a method is to apply an appropriate adhesive to the material surface of the shaft 11 (which may or may not be the polished surface) and then spray and adhere ceramic abrasive powder of a predetermined grain size (e.g., several hundred grit). In this case, it may be possible to apply an adhesive on top of the surface or mix the abrasive powder into paint and apply it to the surface of the material, but it is preferable not to carry out such treatment because the tops of the unevenness on the surface of the powder may become coated (covered) and dulled.

[0029] The shaft 11 is made of a metal such as SUS, steel, or non-ferrous material such as aluminum. The material of the first guide 12 is not particularly limited as long as it is a resin material, and examples thereof include polymeric materials such as POM (polyoxymethylene), ABS resin, and PC (polycarbonate). The elastomer material is not particularly limited, and examples thereof include polymeric materials such as natural rubber, synthetic rubber such as nitrile rubber, hydrogenated nitrile rubber, fluororubber, acrylic rubber, silicone rubber, urethane rubber, chloroprene rubber, ethylene propylene rubber, chlorosulfonated polyethylene, butadiene rubber, epichlorohydrin rubber, isoprene rubber, styrene butadiene rubber, butyl rubber, butadiene rubber, polysulfide rubber, norbornene rubber, and latex.

[0030] <Printer operation example> Next, an example of a partial operation of the printer 100 when a printing process of the consumable S is performed using the platen unit 10 according to this embodiment will be described below. FIG. 9 is a front cross-sectional view showing a state in which a tubular member having a substantially rectangular cross section is set in the printer 100 as the consumable S and transported and printed. The tubular member is not particularly limited, and various long tubes described in, for example, Japanese Patent Application Laid-Open No. 2023-81128 (Patent Application No. 2021-194845) filed by the present applicant can be suitably used. By using such a tube, when the tube is clamped and crushed between the platen unit 10 and the printer head 60, the position of the upper part of the tube is uniquely determined relative to the position of the lower part, which is advantageous because it can suppress positional deviation of the tube (particularly lateral deviation to the left and right in the transport direction) during printing.

[0031] With the cover 2 of the printer 100 open, the consumable S is inserted into the main body 1 through an insertion port SI provided on the right side surface 1SR of the main body 1, and is set so as to fit into the annular recess C1 defined by the first guides 12, 12 of the platen unit 10 and the recess C2 of the second guide. The width of the guides 21, 22 is then appropriately narrowed to guide and hold the consumable S from its sides, creating the state shown in Figure 3. Next, the cover 2 is closed, and the printer head 60 is operated to move it toward the platen unit 10, whereupon the consumable S set between the printer head 60 and the platen unit 10 is pressed by the pressure applied to the platen unit 10 by the head pressing mechanism 61.

[0032] At this time, the consumable S is pressed against the contact surface 10S, which is the bottom surface of the annular recess C1, and the inner wall surface of the first guide, which is the side surface of the annular recess C1, so that the pressing force (biasing force) from the printer head 60 is transmitted to the consumable S without escaping. As a result, the consumable S is held between the printer head 60 and the platen unit 10, and is crushed so that the space of the hollow portion Sh is mainly narrowed, as shown in FIG. 9, without causing misalignment, thereby creating and maintaining a flat printing surface.

[0033] 10 is a cross-sectional view similar to FIG. 8 showing the consumable S set on the platen unit 10, and FIG. 11 is a cross-sectional view similar to FIG. 8 showing the consumable S set on the platen unit 10 being pressed and crushed by the printer head 60. As shown in FIG. 10, in this embodiment, the height H1 of the annular recess C1 when the contact surface 10S of the shaft 11 with the consumable S is taken as the reference is set to be equal to or greater than the thickness of the bottom wall Sb of the consumable S. Also, as shown in FIG. 11, the height H1 of the annular recess C1 is set to be equal to or greater than 1 / 2 (50%) of the height H2 of the consumable S when it is sandwiched between the printer head 60 and the platen unit 10 (approximately 75% in FIG. 11). Furthermore, as shown in Figure 11, when printing the consumable S (when the consumable S is clamped between the printer head 60 and the platen unit 10), the distance G1 between the printer head 60 and the first guide 12 is set to 15% or more (approximately 25% in Figure 11) of the height H2 of the consumable S when clamped and crushed between the printer head 60 and the platen unit 10.

[0034] With the platen unit 10 configured as described above and the printer 100 equipped with it, the consumables S are transported and printed while abutting (contacting) the contact surface 10S of the metal shaft 11. This synchronizes the movement of the shaft 11 with the movement of the consumables S, preventing the consumables S from being distorted during transport. As a result, even if the rotation of the shaft 11 is repeatedly stopped and started to cut the consumables S, bending and distortion of the consumables S are effectively suppressed. This allows the consumables S to easily move in accordance with the rotation of the shaft 11, ensuring reliable printing on the consumables S and preventing poor printing and deterioration of print quality. Furthermore, the first guide 12 prevents the printer head 60 from directly contacting the shaft 11. The first guide 12 is made of a polymeric material and has greater elasticity than the shaft 11. Therefore, even if the printer head 60 comes into contact with the first guide 12, the impact is absorbed, minimizing damage to the printer head 60.

[0035] Furthermore, if the friction coefficient μ1 of the contact surface 10S of the shaft 11 is relatively larger than the friction coefficient μ2 of the material surface of the shaft 11, the contact surface 10S can more easily grip (hold) the consumable S than in the conventional configuration. This more effectively prevents bending and distortion of the consumable S when it is stopped / operated, making it possible to further prevent poor printing and deterioration of print quality on the consumable S.

[0036] Furthermore, if the contact surface 10S is formed by roughening the material surface of the shaft 11, and in particular if the roughening is performed by adhering foreign matter (ceramic powder, abrasive grains, adhesive, etc.) to the material surface of the shaft 11, the workability of the roughening itself is improved, which has the advantage of simplifying the process procedure and increasing productivity.

[0037] Furthermore, first guides 12, 12 for guiding the consumables S are provided on both sides of the contact surface 10S of the shaft 11, and together with the contact surface 10S, an annular recess C1 is defined, so that the consumables S are supported from below and both sides within the annular recess C1. This makes it possible to restrict unwanted movement of the consumables S (particularly lateral shifting to the side, i.e., movement in the left-right direction) and the resulting tilting of the printing surface. As a result, it is possible to further prevent printing defects caused by misalignment of the consumables S.

[0038] Furthermore, in relation to this, if the height H1 of the annular recess C1, when taken from the contact surface 10S of the shaft 11 with the consumable S as the reference, is set to be equal to or greater than the thickness of the bottom wall Sb of the consumable S (FIG. 10), or if the height H1 of the annular recess C1 is set to be equal to or greater than half (50%) of the height H2 of the consumable S when sandwiched between the printer head 60 and the platen unit 10 (FIG. 11), the occurrence of printing defects can be significantly reduced. That is, in these cases, even if the consumable S is a cylindrical member such as a tube, the thick portion of its bottom is reliably supported from the side, and more than half of the lower part of the consumable S is firmly supported from the side. Therefore, misalignment of the consumable S in the annular recess C1 of the platen unit 10, and therefore misalignment of the printing surface, can be more effectively prevented, achieving more stable transport.

[0039] Furthermore, it is even more advantageous if the distance G1 between the printer head 60 and the first guide 12 when printing on the consumable S is 15% or more of the height H2 of the consumable S when it is sandwiched between the printer head 60 and the platen unit 10 (i.e., when it is pressed and crushed) (FIG. 11). That is, with this configuration, interference between the printer head 60 and the first guide 12 when printing on the consumable S is more effectively prevented, so damage to the printer head 60 can be more reliably prevented.

[0040] In addition, if the second guide 16 for guiding the consumable S is provided on the contact surface 10S of the shaft 11 with the consumable S, even if the consumable S is a long member, the consumable S can be reliably inserted into the annular recess C1 on the platen unit 10, which is the printing position. As a result, smoother printing on the consumable S can be achieved.

[0041] The present embodiment has been described above with reference to specific examples. However, this is for the purpose of facilitating understanding of the present disclosure and is not intended to limit the present disclosure. In other words, the present disclosure is not limited to these specific examples. Design modifications to these specific examples made by a person skilled in the art are also encompassed within the technical scope of the present disclosure as long as they comprise the features of the present disclosure. Furthermore, unless otherwise specified, the elements, arrangements, materials, conditions, shapes, dimensions, sizes, scales, etc. of the above-described specific examples are not limited to those exemplified and can be modified as appropriate. Furthermore, the elements of the above-described specific examples can be combined in various ways as appropriate, as long as no technical contradictions arise.

[0042] That is, for example, in the printer 100 using the platen unit 10, it is possible to print not only on consumables S that are hollow members, but also on sheet-like consumables S that are solid members, as long as the printing target has elasticity. Also, the annular recess C1 is not limited to an annular groove, and a structure in which multiple recesses are intermittently formed on the circumferential surface of the shaft 11 along the circumferential direction may be adopted. Furthermore, if the recess C2 of the second guide 16 is structured so that its width gradually narrows from the entrance side to the exit side of the consumables S, it becomes easier to guide the consumables S. [Explanation of symbols]

[0043] 1...Main body, 1B, 2B...Rear side, 1D...Adapter base, 1F, 2F...Front, 1SL, 2SL...Left side, 1SR, 2SR...Right side, 2...Cover, 3...Input / output display, 4...Operation button, 5...Connector, 6...Operation unit, 10...Platen unit, 10S...Contact surface, 11...Shaft, 12...First guide, 13...Bearing, 14...First shaft bush, 15...Second shaft bush, 16...Second guide, 17...Holder guide, 18...Guide stopper, 20...Positioning guide, 21, 22...Guide, 30...Feed amount detection Output unit, 31...feed amount detection roller, 40...cut unit, 41...half cutter, 42...receiver, 43...full cutter, 50...ink ribbon unit, 51...bobbin, 51r...reel, 52...cassette, 52r...reel, 60...printer head, 61...head pressing mechanism, 100...printer, C1...annular recess, C2...recess, E1...retaining receiver, E2...retaining pawl, G1...gap, J...bearing part, PG...platen gear, R...ink ribbon, S...consumables (printing object), Sb...bottom wall, Sh...hollow part, SI...insertion port, SO...exit port

Claims

1. a shaft that is disposed in a position facing a printer head that prints on a print target made of an elastic member, and that conveys the print target by rotating while sandwiching the print target between the printer head and the shaft; a first guide provided on both sides of a contact surface of the shaft that comes into contact with the target to be printed, the first guide defining an annular recess together with the contact surface and guiding the target to be printed from the side when the target to be printed is transported; Equipped with The shaft is made of a metal material, and the first guide is made of a polymer material. Platen unit.

2. The coefficient of friction at the contact surface is set to be larger than the coefficient of friction at a material surface of a portion different from the contact surface. The platen unit according to claim 1 .

3. The contact surface is a surface that has been subjected to a roughening treatment on the material surface. The platen unit according to claim 2.

4. the height of the annular recess with respect to the contact surface being equal to or greater than half the height of the printing target when sandwiched between the printer head and the shaft; 4. The platen unit according to claim 1.

5. In the case where the printing target is cylindrical, a height of the annular recess with respect to the contact surface being equal to or greater than a thickness of a bottom wall of the printing target; 4. The platen unit according to claim 1.

6. a printer head that prints on a printing target made of an elastic material; The platen unit according to claim 1; A printer comprising:

7. a distance between the printer head and the first guide when printing on the print object is 15% or more of the height of the print object when it is held between the printer head and the shaft; 7. The printer according to claim 6.

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