Patent ID: 12214667

DESCRIPTION OF EMBODIMENTS

Hereinafter, the present disclosure will be schematically described.

A power transmission mechanism according to a first aspect of the present disclosure includes an operation unit, a drive source configured to generate power for operating the operation unit, and a gear train mechanism including a plurality of power transmission gears of which rotation centers are arranged in a staggered pattern when viewed from an axial direction and configured to transmit the power by rotating the plurality of power transmission gears. The gear train mechanism includes a first gear as the power transmission gear located most downstream in a power transmission direction in which the power is transmitted from the drive source to the operation unit, a second gear as the power transmission gear engaged with the first gear and transmitting the power to the first gear, and a dummy gear not having a function of transmitting the power. The dummy gear is engaged with the first gear and has a rotation center arranged in a staggered pattern with respect to the first gear and the second gear as viewed from the axial direction.

According to the present aspect, a dummy gear that does not have a function of transmitting power is provided, the dummy gear engages with the first gear, and the rotation center of the dummy gear is disposed in a staggered pattern with respect to the first gear and the second gear when viewed from the axial direction. That is, the power transmission mechanism is provided with the dummy gear capable of suppressing the misalignment of the first gear even when a force is applied to the first gear located most downstream in the power transmission direction with the rotation of the power transmission gear. Therefore, it is possible to suppress tooth skipping of each power transmission gear including the power transmission gear located most downstream in the gear train mechanism including the plurality of power transmission gears.

A power transmission mechanism according to a second aspect of the present disclosure is an aspect dependent on the first aspect, in which the operation unit is a conveyance unit that conveys a medium.

According to the present aspect, the operation unit is the conveyance unit that conveys a medium. Therefore, the conveyance accuracy of media in the conveyance unit can be improved.

A power transmission mechanism according to a third aspect of the present disclosure is an aspect dependent on the first or second aspect, in which the diameter of the dummy gear is smaller than the diameter of the first gear.

According to the present aspect, the diameter of the dummy gear is smaller than the diameter of the first gear. Therefore, since the dummy gear can be made small, the power transmission mechanism can be downsized.

A power transmission mechanism according to a fourth aspect of the present disclosure is an aspect dependent on the first or second aspect, in which the diameter of the dummy gear is larger than the diameter of the first gear.

According to the present aspect, the diameter of the dummy gear is larger than the diameter of the first gear. Since the rotation speed of the dummy gear can be reduced by driving the large dummy gear, the power transmission mechanism can be reduced in noise.

A power transmission mechanism according to a fifth aspect of the present disclosure is an aspect dependent on any one of the first to fourth aspects, in which a rotating shaft of the dummy gear is configured to have a first shaft width that is a shaft width in a first direction toward a rotation center of the first gear is wider than a second shaft width that is a shaft width in a second direction orthogonal to the first direction.

According to the present aspect, a rotating shaft of the dummy gear is configured to have a first shaft width that is a shaft width in a first direction toward a rotation center of the first gear is wider than a second shaft width that is a shaft width in a second direction orthogonal to the first direction. Therefore, the dummy gear can particularly effectively suppress the misalignment of the first gear and can particularly effectively suppress tooth skipping of the first gear.

A liquid ejecting device according to a sixth aspect of the present disclosure includes a power transmission mechanism according to any one of the first to fifth aspects and a liquid ejecting unit configured to eject liquid to a medium.

According to the present aspect, in addition to the power transmission mechanism, a liquid ejecting unit that ejects liquid to the medium is provided. Therefore, in the liquid ejecting device including the liquid ejecting unit that ejects liquid onto the medium, the operation accuracy in the operation unit can be improved.

Hereinafter, the present disclosure will be specifically described. First, an outline of an inkjet printer1that is a liquid ejecting device including a power transmission mechanism100according to the present disclosure will be described. Hereinafter, the inkjet printer1is simply referred to as the printer1. Hereinafter, the direction in which a medium is fed and the direction in which power generated by a drive source is transmitted may be referred to as “downstream”, and the opposite direction may be referred to as “upstream”.

As shown inFIG.1, the printer1includes an accommodation unit2that accommodates media. A plurality of media can be loaded in the accommodation unit2. Note that the printer1according to the present embodiment can be additionally provided with a medium accommodation unit capable of accommodating media below the accommodation unit2. However, the printer is not limited to such a configuration.

The printer1is provided with a pickup roller10that feeds a medium accommodated in the accommodation unit2in a conveying direction A. A separation roller11is provided downstream of the pickup roller10in the medium conveyance path. The medium is conveyed in the conveying direction A toward the separation roller11by the pickup roller10and then conveyed in the conveying direction A by the pickup roller10and the separation roller11.

Here, as illustrated inFIG.1and the like, a retard roller12is provided at a position facing the separation roller11. As described above, in the printer1according to the present embodiment, a plurality of media can be stacked in the accommodation unit2. When the first medium which is the uppermost medium stacked in the accommodation unit2is conveyed, the leading end of the second medium is made to abut on the retard roller12so that the second medium conveyed following the first medium is not doubly fed. The first medium that has reached a nip point N1between the separation roller11and the retard roller12is conveyed in the conveying direction A by the pickup roller10and the separation roller11, but the leading end of the second medium is made to abut on the retard roller12, so that the second medium is stopped without being conveyed and separated from the first medium.

The pickup roller10and the separation roller11rotate in the first rotating direction C1when conveying the medium. The pickup roller10and the separation roller11are connected to the motor8electrically connected to the control unit7including a CPU, a storage unit, and the like via a plurality of gears and the like and are driven by the driving force of the motor8. The pickup roller10and the separation roller11, which are operation units, and the motor8, which is a drive source, each are one of the constituent members that constitute the power transmission mechanism100described later. As illustrated inFIG.1, the printer1according to the present embodiment includes a reception unit20that receives an execution command of a recording operation from a user, that is, a conveyance instruction of the medium M.

As illustrated inFIG.1and the like, the printer1includes an intermediate roller13and two driven rollers14provided at positions facing the intermediate roller13in the conveyance path of the medium. The intermediate roller13is also an operation unit similarly to the pickup roller10and the separation roller11and is connected to the motor8via a plurality of gears and the like. The leading end of the medium conveyed in the conveying direction A by the pickup roller10and the separation roller11reaches a nip point N2between the intermediate roller13and a first driven roller14A of the driven rollers14.

After the leading end of the medium reaches the nip point N2, the medium is conveyed in the conveying direction A by the intermediate roller13and the first driven roller14A. Further, the leading end of the medium conveyed in the conveying direction A by the intermediate roller13and the first driven roller14A reaches a nip point N3between the intermediate roller13and a second driven roller14B of the driven rollers14. After the leading end reaches the nip point N3, the medium is conveyed in the conveying direction A by the intermediate roller13and the two driven rollers14. The intermediate roller13rotates in the first rotating direction C1when conveying the medium. On the other hand, both the first driven roller14A and the second driven roller14B rotate in a second rotating direction C2when conveying the medium.

As illustrated inFIG.1and the like, the printer1is provided with an insertion portion3into which a medium can be manually inserted by a user. The medium inserted into the insertion portion3is conveyed in the conveying direction A at the nip point N3between the intermediate roller13and the second driven roller14B. Specifically, as illustrated inFIG.1, the medium accommodated in the accommodation unit2is conveyed in a conveying direction A1of the conveying directions A to the nip point N3, and the medium inserted into the insertion portion3is conveyed in a conveying direction A2of the conveying directions A to the nip point N3.

The medium whose leading end reaches the nip point N3is conveyed by the intermediate roller13toward a position facing a line head6provided in a head unit5that is provided downstream of the nip point N3in the conveying direction A. A conveyance roller pair9is provided upstream and downstream of the head unit5in the conveying direction A. The conveyance roller pair9includes a driving roller driven by the motor8and a driven roller that is driven to rotate in contact with the driving roller. That is, the driving roller of the conveyance roller pair9can also be regarded as an operation unit as one of the components constituting the power transmission mechanism100.

The line head6is connected to an ink cartridge21containing ink via a tube22. That is, the line head6is a liquid ejecting unit having a configuration capable of ejecting ink sent from the ink cartridge21through the tube22toward the medium, in other words, a recording unit.

The medium receiving a feeding force from the conveyance roller pair9is sent to a recording position facing the line head6. The line head6constitutes the head unit5. The line head6ejects ink, which is an example of liquid, onto the image forming surface of the medium to execute recording. The line head6is an ink ejection head configured such that nozzles that eject ink cover the entire region in a width direction B and is configured as an ink ejection head capable of performing recording in the entire region of the medium in the width direction B without moving in the width direction B. However, the ink ejection head is not limited thereto and may be of a type that is mounted on a carriage and ejects ink while moving in the width direction B. In addition, it is also possible to use a recording unit having a configuration other than that of the ink ejection head, such as a thermal transfer recording unit.

The medium on which recording has been performed by the line head6is conveyed by the conveyance roller pair9and is discharged to a discharge tray4. There is no particular limitation on the configuration of the accommodation unit2that accommodates media, the insertion portion3into which a medium is inserted, and the discharge tray4on which discharged media can be stacked. The accommodation unit2and the discharge tray4may be configured to be capable of stacking a plurality of media.

As described above, the printer1according to the present embodiment includes the power transmission mechanism100, which will be described in detail below, and the line head6, which is a liquid ejecting unit that ejects ink, which is liquid, onto a medium. Due to such a configuration, in the printer1including the liquid ejecting unit that ejects liquid onto a medium, it is possible to improve the operation accuracy in the operation unit. Hereinafter, the power transmission mechanism100, which is a main part of the printer1according to the present embodiment, will be described in detail with reference toFIGS.2to5.

As described above, a power transmission mechanism100A according to the present embodiment as the power transmission mechanism100includes a pickup roller10, a separation roller11, an intermediate roller13, and the like as the operation units, and a motor8as the drive source that generates power for operating these operation units. Furthermore, as illustrated inFIG.2, the power transmission mechanism includes the gear train mechanism110that includes a plurality of power transmission gears101,102,103, and104in which rotation centers101c,102c,103c, and104care arranged in a staggered pattern when viewed from the width direction B corresponding to the axial direction and transmits power generated by the motor8by rotating the plurality of power transmission gears101,102,103, and104. The rotation centers101c,102c,103c, and104care arranged in a staggered pattern means that they are not arranged on a straight line but arranged alternately. In this specification, the power transmission mechanism100includes the operation unit and the drive source but may not include the operation unit and the drive source.

Here, a gear81is a gear attached to the rotating shaft of the motor8. By driving the motor8to rotate the rotating shaft of the motor8and the gear81in the first rotating direction C1, the power transmission gear101engaged with the gear81rotates in the second rotating direction C2. When the power transmission gear101rotates in the second rotating direction C2, the power transmission gear102engaged with the power transmission gear101rotates in the first rotating direction C1. When the power transmission gear102rotates in the first rotating direction C1, the power transmission gear103engaged with the power transmission gear102rotates in the second rotating direction C2. When the power transmission gear103rotates in the second rotating direction C2, the power transmission gear104engaged with the power transmission gear103rotates in the first rotating direction C1. Here, the power transmission gear104is a power transmission gear located most downstream of the gear train mechanism110of the power transmission mechanism100A according to the present embodiment, and power from the motor8is transmitted to the pickup roller10, the separation roller11, the intermediate roller13, and the like via the power transmission gear104.

In other words, the gear train mechanism110of the power transmission mechanism100A according to the present embodiment includes the power transmission gear104that is the first gear as the power transmission gear located most downstream in a power transmission direction in which power is transmitted from the motor8, which is a drive source, to an operation unit and the power transmission gear103that is the second gear as a power transmission gear engaged with the power transmission gear104and transmitting power generated by the motor8to the power transmission gear104. Furthermore, as illustrated inFIG.2, the gear train mechanism110of the power transmission mechanism100A according to the present embodiment includes a dummy gear90having no function of transmitting power generated by the motor8. The dummy gear90is engaged with the power transmission gear104, and a rotation center90cis arranged in a staggered pattern as viewed from the width direction B with respect to the power transmission gear104and the power transmission gear103.

That is, the power transmission mechanism100A according to the present embodiment includes the dummy gear90capable of suppressing the misalignment of the power transmission gear104even when a force is applied to the power transmission gear104located most downstream in the power transmission direction as the power transmission gears101,102,103, and104rotate. Therefore, the power transmission mechanism100A according to the present embodiment can suppress the tooth skipping of the power transmission gears101,102,103, and104including the power transmission gear104which is the gear located most downstream in the power transmission direction in the gear train mechanism110including the plurality of power transmission gears. In the present embodiment, the four power transmission gears101,102,103, and104are used, but the number of power transmission gears constituting the gear train mechanism110is not particularly limited.

Here, in the power transmission mechanism100A according to the present embodiment, the operation unit is the conveyance roller that conveys media. Specifically, the pickup roller10, the separation roller11, the intermediate roller13, and the like are provided. Therefore, in the power transmission mechanism100A according to the present embodiment, it is possible to improve the conveyance accuracy of media in the conveyance unit. However, the operation unit is not limited to the conveyance unit. The operation unit may be a constituent member that performs an operation different from the conveyance of media.

Hereinafter, the reason why the power transmission mechanism100A according to the present embodiment can suppress tooth skipping of the power transmission gear104, which is the gear located most downstream in the power transmission direction, will be described in comparison with a power transmission mechanism100B inFIG.3and a power transmission mechanism100C inFIG.4used in the printer according to the reference example. First, the reason why tooth skipping of the power transmission gears occurs in the power transmission mechanism100B inFIG.3will be described. InFIGS.3and4, the same components as those inFIG.2are denoted by the same reference numerals.

As illustrated inFIG.3, the power transmission mechanism100B includes a plurality of power transmission gears101,102,103, and104having rotation centers101c,102c,103c, and104carranged in a straight line when viewed from the width direction B. When the plurality of power transmission gears are provided in such an arrangement, a power transmission gear101rotates in the second rotating direction C2by rotating a gear81in the first rotating direction C1. At this time, the power transmission gear101receives a force in the direction Fa corresponding to the downward direction in the drawing from the gear81. Therefore, the power transmission gear101is likely to be misaligned in the same direction F1as the direction Fa. When the power transmission gear101is misaligned, tooth skipping is likely to occur between the gear81and the power transmission gear101and between the power transmission gear101and the power transmission gear102. Furthermore, when the power transmission gear101rotates the power transmission gear102, a reaction force from the power transmission gear102is received in the same direction as the direction Fa, so that tooth skipping is more likely to occur.

When the power transmission gear101rotates in the second rotating direction C2, the power transmission gear102rotates in the first rotating direction C1. At this time, the power transmission gear102receives a force in a direction Fb corresponding to an upward direction in the drawing from the power transmission gear101, and the power transmission gear102is likely to be misaligned in the same direction F2as the direction Fb. Similarly, the power transmission gear103is likely to be misaligned in the same direction F3as the direction Fc by receiving a force in the direction Fc corresponding to the downward direction in the drawing from the power transmission gear102, and the power transmission gear104is likely to be misaligned in the same direction F4as a direction Fd by receiving a force in the direction Fd corresponding to the upward direction in the drawing from the power transmission gear103. Further, similarly to the power transmission gear101, the power transmission gear102and the power transmission gear103receive reaction forces from the rotating gears and thus are more likely to be misaligned. Here, the power transmission mechanism100B has the gear81and the power transmission gears101,102,103, and104arranged in a straight line and hence is not configured to prevent one gear from being misaligned with respect to adjacent gears, and in other words, is not configured to make adjacent gears receive a force applied to one gear. That is, the power transmission mechanism100B is not configured to suppress tooth skipping.

Next, the reason why the tooth skipping of power transmission gears occurs in the power transmission mechanism100C inFIG.4will be described. As illustrated inFIG.4, the power transmission mechanism100C includes a plurality of power transmission gears101,102,103, and104having rotation centers101c,102c,103c, and104carranged in a staggered pattern when viewed from the width direction B. When the plurality of power transmission gears are provided in such an arrangement, a power transmission gear101rotates in the second rotating direction C2by rotating a gear81in the first rotating direction C1. At this time, the power transmission gear101receives a force in the direction Fa in the drawing from the gear81. However, the power transmission gear102is disposed on the direction Fa side with respect to the power transmission gear101. For this reason, it is assumed that the force applied to the power transmission gear101in the direction Fa is received by the power transmission gear102, the force acts on the power transmission gear101in the direction F1corresponding to the downward direction in the drawing, and misalignment easily occurs in the direction F1. However, actually, since the gap between the gear81and the power transmission gear102is smaller than the outer diameter of the power transmission gear101, the power transmission gear101is less likely to be misaligned.

When the power transmission gear101rotates in the second rotating direction C2, the power transmission gear102rotates in the first rotating direction C1. At this time, the power transmission gear102receives a force in the direction Fb from the power transmission gear101. However, the power transmission gear103is disposed on the direction Fb side with respect to the power transmission gear102. For this reason, it is assumed that the force applied to the power transmission gear102in the direction Fb is received by the power transmission gear103, the force acts on the power transmission gear102in the direction F2corresponding to the upward direction in the drawing, and misalignment easily occurs in the direction F2. However, actually, since the gap between the power transmission gear101and the power transmission gear103is smaller than the outer diameter of the power transmission gear102, the power transmission gear102is less likely to be misaligned.

Similarly, when the power transmission gear102rotates in the first rotating direction C1, the power transmission gear103rotates in the second rotating direction C2. At this time, the power transmission gear103receives a force in the direction Fc from the power transmission gear102. However, the power transmission gear104is disposed on the direction Fc side with respect to the power transmission gear103. For this reason, it is assumed that the force applied to the power transmission gear103in the direction Fc is received by the power transmission gear104, the force acts on the power transmission gear103in the direction F1corresponding to the downward direction in the drawing, and misalignment easily occurs in the direction F3. However, actually, since the gap between the power transmission gear102and the power transmission gear104is smaller than the outer diameter of the power transmission gear103, the power transmission gear103is less likely to be misaligned.

When the power transmission gear103rotates in the second rotating direction C2, the power transmission gear104rotates in the first rotating direction C1. At this time, the power transmission gear104receives a force in a direction Fd from the power transmission gear103. However, no particular constituent member is disposed on the direction Fd side with respect to the power transmission gear104. Therefore, a force acts on the power transmission gear104in the direction F4corresponding to the same direction as the direction Fd, and misalignment easily occurs in the direction F4. As described above, in the power transmission mechanism100C inFIG.4, the power transmission gears101,102, and103are less likely to be misaligned and less likely to cause tooth skipping, but the power transmission gear104is likely to be misaligned and cause tooth skipping.

Therefore, as illustrated inFIG.2, the power transmission mechanism100A according to the present embodiment includes the dummy gear90downstream of the power transmission gear104in the power transmission direction with respect to the power transmission mechanism100C illustrated inFIG.4. That is, the power transmission gear104rotates in the first rotating direction C1with the rotation of the power transmission gear103in the second rotating direction C2, and the power transmission gear104receives the force in the direction Fd from the power transmission gear103, but the dummy gear90is disposed on the direction Fd side with respect to the power transmission gear104. Therefore, in the power transmission mechanism100A according to the present embodiment, it is assumed that the force applied to the power transmission gear104in the direction Fd is received by the dummy gear90, the force acts on the power transmission gear104in the direction F4corresponding to the upward direction in the drawing, and misalignment easily occurs in the direction F4. However, actually, since the gap between the power transmission gear103and the dummy gear90is smaller than the outer diameter of the power transmission gear104, the power transmission gear104is less likely to cause misalignment. Therefore, in the power transmission mechanism100A according to the present embodiment, the power transmission gears101,102, and103are less likely to be misaligned and cause tooth skipping, and the power transmission gear104is also less likely to be misaligned and cause tooth skipping.

Here, as illustrated inFIG.2, in the power transmission mechanism100A according to the present embodiment, the diameter (outer diameter) of the dummy gear90is smaller than the diameter (outer diameter) of the power transmission gear104which is the first gear adjacent to the dummy gear90. With such a configuration, the dummy gear90can be reduced in size, and the power transmission mechanism100can be downsized.

However, the present disclosure is not limited to such a configuration. The diameter of the dummy gear90in the power transmission mechanism100may be larger than the diameter of the first gear adjacent to the dummy gear90. Since the rotation speed of the dummy gear90can be reduced by driving the large dummy gear90, the power transmission mechanism100can be reduced in noise by making the diameter of the dummy gear90larger than the diameter of the first gear adjacent to the dummy gear90.

Here, as illustrated inFIG.5, in the power transmission mechanism100A according to the present embodiment, a rotating shaft91of the dummy gear90does not rotate following the rotation of the dummy gear90but is fixed, and a first shaft width L1, which is the shaft width in a first direction D1toward the rotation center104cof the power transmission gear104as the first gear, is configured to be wider than a second shaft width L2, which is the shaft width in a second direction D2orthogonal to the first direction D1. Note that the rotating shaft91corresponds to the rotation center90cinFIG.2, and the first direction D1corresponds to the direction Fd inFIG.2. With such a configuration, the rotating shaft91can effectively receive the force applied from the power transmission gear104, and the dummy gear90can particularly effectively suppress the misalignment of the power transmission gear104. Therefore, it is possible to particularly effectively suppress tooth skipping of the power transmission gear104.

The present disclosure is not limited to each embodiment described above, many variations are possible within the scope of the present disclosure as described in the appended claims, and it goes without saying that such variations also fall within the scope of the present disclosure. For example, the operation unit may be a liquid feeding mechanism such as a tube pump that feeds ink from the ink cartridge21to the line head6, and the power transmission mechanism according to the present disclosure may be applied to the power transmission mechanism. In addition, the discharge tray4may be configured to be movable in the vertical direction according to the number of stacked media discharged and the like, the operation unit may be a moving mechanism, and the power transmission mechanism according to the present disclosure may be applied to the power transmission mechanism. Furthermore, for example, the present disclosure is not limited to the printer and may be applied to a scanner, an intermediate unit provided between various devices, a conveyance device in a finisher, or the like.