JP2007118442A - Inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mechanism of automatically adjusting a paper gap which is suitable for a mobile printer. <P>SOLUTION: Paper gap adjustment is carried out by rotating a platen by a cam mechanism arranged at a platen lower part. Driving force of a cam is transmitted via a pendulum gear from a paper discharge roller. The pendulum gear can take a driving transmission phase when the carriage is present at a specific position. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus that records an image by ejecting ink onto a recording material, and more particularly to a paper gap adjustment technique.

  In an ink jet recording apparatus, it is necessary to adjust the distance between a recording head and a recording material according to printing conditions in order to improve recording image quality and transport stability. I want to make adjustments automatically or semi-automatically to improve user convenience. The inside of the recording apparatus is constituted by various drive mechanisms, and the internal mechanism becomes complicated and the apparatus tends to be enlarged as the function is improved. Inside the device, the drive mechanism has been devised in various ways.

On the other hand, in recent years, with the development of information communication infrastructure and the increase in the size and capacity of information recording media, it has become possible to output information anytime and anywhere. As a powerful means for outputting information, a recording apparatus that is small and lightweight and excellent in portability is desired.
JP 2002-254677 A

  In the conventional automatic paper spacing adjustment method by raising and lowering the carriage, the product thickness dimension becomes large, and it is difficult to realize automatic paper spacing adjustment in a thin portable printer. It is a problem to achieve automatic adjustment between sheets in a thin portable printer with a simple configuration.

  A first aspect of the present invention is an ink jet recording apparatus that forms an image on a recording material using a recording unit that ejects ink to record an image, and is coaxial with one drive shaft related to conveyance of the recording material. And a swing gear capable of swinging between the first dead center and the second dead center following the forward / reverse rotation of the transport system, and the swing of the swing gear Swing gear holding means for limiting the process to a drive output position between the first dead center and the second dead center, a recording material support means that can be moved up and down substantially, and a lower portion of the recording material support means And a supporting member driving means for obtaining drive transmission from the oscillating gear and substantially moving the recording material supporting means up and down when the oscillating gear is in the drive output position. This realizes automatic adjustment between sheets in a thin printer.

  Second, the rocking shaft of the rocking gear is used as a paper discharge roller, and the recording material support means rotates around the upstream side of conveyance. By adjusting the paper interval by raising and lowering the platen downstream side, the rubbing between the leading edge of the recording paper and the recording head can be reduced. By adopting a configuration in which a platen drive system disposed under the platen is driven by drive transmission from a paper discharge roller, the printer can be made thinner.

  Third, the planetary gear holding means comes into contact with the carriage in the middle from the first dead center to the second dead center, so that the phase of the rocking gear remains at the drive output position. This is a configuration that does not require a special secondary clutch that controls the process of the swinging gear by using the carriage.

  According to the present invention, it is possible to perform automatic adjustment between paper sheets with a simple configuration with space saving, small size and low cost, and a small and high quality recording apparatus can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is an external perspective view showing a schematic external configuration of an inkjet recording apparatus embodying the present invention. Reference numeral 1 denotes an apparatus housing having a recording engine, an electric circuit board, and the like. A recording material (not shown), hereinafter referred to as a recording sheet, is stood against the sheet feeding tray 2 and fed from the sheet feeding port 3. The recording paper is discharged from the paper discharge port 4.

  FIG. 2 is a perspective view showing the main configuration of the recording engine of the embodiment. In FIG. 2, a recording head 8 and an ink tank 7 are mounted on the carriage 6. The carriage 6 is driven by the carriage motor 11 through the carriage belt 12 in the main scanning direction indicated by the arrow A along the carriage shaft 9 and the carriage guide 10. The transport roller 15 and the paper discharge roller 16 are driven by the transport motor 13 through the transport drive transmission system 14 in the sub-scanning direction indicated by the arrow B. Reference numeral 17 denotes a platen serving as a recording material support means. A maintenance unit 18 includes a head protection cap and the like, and maintenance of the recording head is performed in cooperation with a pump system (not shown).

  The manner in which the recording material support means is substantially raised and lowered by the support material driving means, that is, the schematic configuration of the platen rotation system will be described with reference to FIGS. Hereinafter, the recording material support means is a platen, and the support material drive means is a series of platen drive mechanism systems including gears, cams, shafts, and the like, and the substantially raising and lowering of the platen is the rotation of the platen. . 3 is a perspective view from the top, and FIG. 4 is a perspective view from the back side. The platen 17 is pivotally supported on the main chassis 5 by two left and right platen rotation shafts 25 on the upstream side. On the downstream side of the platen, two left and right platen springs 27 are suspended between the main chassis 5 and the platen 17, and the platen is biased downward. Reference numeral 24 denotes a platen camshaft that is rotatably supported by the main chassis 5 at both left and right ends. The two left and right platen cams 26 into which the platen cam shaft 24 is press-fitted can rotate integrally with the platen cam shaft 24, and support the downstream part of the platen from below against the urging force of the platen spring 27. The cam profiles of the two left and right platen cams 26 are in phase. The cam click spring 28 stabilizes the platen cam 26 at a predetermined phase, and is a metal plate spring having one end fixed to the main chassis 5. The cam sensor 29 is used to initialize the phase of the platen cam 26. A paper discharge shaft 19 that is a core of the paper discharge roller 16 is pivotally supported by the main chassis 5 so that both left and right ends can rotate freely. An input gear 21 that is a swing gear is connected to a paper discharge roller gear 20 that rotates integrally with the paper discharge shaft 19 via a planetary holder 22. The input gear 21 can swing between a first dead center and a second dead center described later. The discharge roller gear 20 is a sun gear, and the input gear 21 is a planetary gear. The input gear 21 can swing around the paper discharge shaft 19 and has a position that enables transmission of drive to the platen gear 23 in the middle of the swing range. The platen gear 23 rotates integrally with the platen camshaft 24, and selectively receives drive transmission from the input gear 21. By adjusting the paper interval by raising and lowering the platen downstream side, the rubbing between the leading edge of the recording paper and the recording head can be reduced. By adopting a configuration in which a platen drive system disposed under the platen is driven by drive transmission from a paper discharge roller, the printer can be made thinner.

  FIG. 5 is an enlarged perspective view of the vicinity of the input gear 21. FIG. A paper discharge shaft 19 is press-fitted into the paper discharge roller gear 20. The planetary holder 22 can be smoothly rotated with respect to the paper discharge shaft 19. The input gear 21 is rotatably supported by the planetary holder 22, is always connected to the paper discharge roller gear 20, and can be selectively connected to the platen gear 23. The input gear 21 is elastically held by two planetary side plates 30 that are part of the planetary holder 22. Due to this frictional load, the planetary pendulum movement of the input gear 21 is stably performed.

  FIG. 6 is an enlarged perspective view of the vicinity of the platen cam 26 on the platen gear 23 side. The cam click spring 28 is engaged with a cam click groove 31 formed integrally with the platen cam 26 in a predetermined cam phase. The cam sensor plate 32 formed integrally with the platen cam 26 at a predetermined position is detected by the cam sensor 33 which is a transmission type photosensor, and the phase is initialized. The cam sensor 33 is fixed to the main chassis 5 and is electrically connected to a circuit board (not shown).

  7 to 9 are side views for explaining the substantially up-and-down position of the platen 17, that is, the rotational position. 7 to 9, only one of the pair of left and right cams is shown, but the other cam is the same. In this example, FIG. 7 is a special paper position, FIG. 8 is a plain paper position, and FIG. 9 is an envelope position. By rotating the platen, the gap between the recording head and the recording sheet, that is, the gap between the sheets, is adjusted. 7 to 9, the platen 17 is in contact with the cam surface of the platen cam 26 at the platen cam follower 34 united with the platen 17 by the urging force of the platen spring 27. At each position, the cam click spring 28 wedges the platen cam 26 to stabilize the phase of the platen cam 26. In FIG. 7, the platen cam 26 fully lifts up the platen cam follower 34. This is the position where the gap between the sheets is the narrowest. This is a special paper position corresponding to special glossy paper for obtaining photographic image quality. FIG. 8 shows a state in which the platen cam 26 is driven by a predetermined amount in the direction of arrow C from the state of FIG. 7 and the platen 17 is substantially lowered. The platen cam follower 34 is in contact with the cam profile surface of the platen cam 26 that is one step lower than the state shown in FIG. The paper interval is set to a predetermined amount from the special paper position in FIG. 7, and a paper interval corresponding to plain paper is set. FIG. 9 shows a state in which the platen cam 26 is driven by a predetermined amount in the direction of arrow C from the state of FIG. The platen cam follower 34 is in contact with the lowest cam profile surface of the platen cam 26. The rotation of the platen 17, that is, the substantially descending amount is maximized, and the paper interval for envelope printing is set. When the platen cam 26 is driven by a predetermined amount in the arrow C direction from the state shown in FIG. 9, ie, the envelope position, the special paper position shown in FIG. 7 is reached. The sheet spacing is set by the platen substantially lifting system without moving the carriage up and down. By effectively utilizing the space below the platen, the printer is made thinner.

  The drive transmission to the platen cam 26, that is, the drive transmission to the platen gear 23 will be described with reference to FIGS. FIG. 10 shows a state in which the swing system is at the first dead center, and shows the phase of the planetary holder 22 at the time of forward conveyance during the printing operation. Since the recording paper is sequentially fed, the paper discharge shaft 19 and the planetary holder 22 are rotated and rotated in the direction of arrow D. A first planetary stopper 35 that is a part of the planetary holder 22 is in contact with the carriage guide 10. At this time, the input gear 21, which is a planetary gear, is separated from the platen gear 23, and drive transmission is not performed to the platen substantially lifting system. FIG. 11 shows a state in which the oscillation system is at the second dead center, and shows the phase of the planetary holder 22 at the time of reverse conveyance during the printing operation. Since the recording paper is reversely fed, the paper discharge shaft 19 and the planetary holder 22 are rotated and rotated in the direction of arrow E. A second planetary stopper 36 that is a part of the planetary holder 22 is in contact with the carriage guide 10. At this time, the input gear 21, which is a planetary gear, is separated from the platen gear 23, and drive transmission is not performed to the platen substantially lifting system. FIG. 12 and FIG. 13 are diagrams showing how the drive transmission of the platen 17 to the substantially lifting system is performed. After the forward movement operation of the paper discharge shaft 19, the carriage 6 is moved immediately above the planetary holder 22 and stopped. Here, when reverse feed drive is applied to the paper discharge shaft 19, the planetary holder 22 rotates in the direction of arrow E. Thereafter, the tip of the second planetary stopper 36 comes into contact with a planetary holder contact portion 37 which is a swinging gear holding means which is a part of the carriage 6. At this time, the input gear 21 is in a drive connection position with the platen gear 23. When the predetermined amount of driving is continued in the direction of arrow E, the platen gear 23 rotates by a predetermined amount, and the desired sheet spacing position shown in FIGS. 7 to 9 is set. During normal printing operations, there are no restrictions on the forward and backward feeding operations of the transport system. By using the carriage for the swinging gear holding means for setting the connecting position of the swinging gear, it is not necessary to newly provide a new element. With a simple and space-saving clutch system configuration, drive transmission is performed to the platen substantially lifting system. This makes it possible to achieve automatic adjustment between sheets without increasing the number of drive sources at a low cost and in a small space.

External perspective view of the embodiment The perspective view which shows the main structure of the recording engine of an Example. The perspective view which shows the structure of the platen rotation system of an Example. The back side perspective view showing composition of a platen rotation system of an example Enlarged perspective view of the platen drive transmission system of the embodiment Enlarged perspective view of the vicinity of the platen cam of the embodiment The side view which shows the rotation position of the platen of an Example The side view which shows the rotation position of the platen of an Example The side view which shows the rotation position of the platen of an Example The expanded side view which shows the phase of the input gear of an Example The expanded side view which shows the phase of the input gear of an Example The expanded side view which shows the phase of the input gear of an Example The expanded side view which shows the phase of the input gear of an Example

Explanation of symbols

1 Device housing
2 Paper tray
3 Paper feed slot
4 Paper exit
5 Main chassis
6 Carriage
7 Ink tank
8 Recording head
9 Carriage shaft
10 Carriage guide
11 Carriage motor
12 Carriage belt
13 Transport motor
14 Transport drive transmission system
15 Transport roller
16 Paper discharge roller
17 Platen
18 Maintenance unit
19 Output shaft
20 Output roller gear
21 Input gear
22 Planetary holder
23 Platen gear
24 Platen camshaft
25 Platen rotation axis
26 Platen cam
27 Platen spring
28 Cam click spring
29 Cam sensor
30 Planetary side plate
31 Cam click groove
32 Cam sensor plate
33 Cam sensor
34 Platencom follower
35 First planetary stopper
36 Second planetary stopper
37 Planet holder contact part

Claims (3)

  An ink jet recording apparatus that forms an image on a recording material using a recording unit that records an image by ejecting ink, wherein the driving force of the conveying system is coaxial with one driving shaft for conveying the recording material. A swing gear that is transmitted and can swing between a first dead center and a second dead center following the forward and reverse rotation of the transport system, and the swing step of the swing gear is the first dead center. Oscillating gear holding means for limiting the drive output position between the first dead center and the second dead center, the recording material supporting means that can be moved up and down substantially, and the oscillating gear disposed below the recording material supporting means. An ink jet recording apparatus comprising: support material driving means for obtaining drive transmission from the rocking gear and substantially moving the recording material support means up and down when in the drive output position.   2. The ink jet recording apparatus according to claim 1, wherein the swing shaft of the swing gear is a paper discharge roller, and the recording material support means rotates around the upstream side of conveyance.   3. The ink jet recording apparatus according to claim 1, wherein the swinging gear holding means is a part of a carriage.

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