JP2009007112A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device improved in productivity when printing photographs and post cards, improved in productivity when printing a small-size paper by using two recording medium housing means, and capable of preventing a rub and a jam of the recording medium. <P>SOLUTION: Each of recording medium housing means 30a and 30b has a fixed guide 73 fixed for positioning in a direction crossing the recording medium conveying direction and a movable guide 34 opposite to the fixed guide 73 so as to be moved in directions for widening/narrowing a clearance between the fixed guide 73. The fixed guide 73 of the first recording medium housing means 30a and the fixed guide 73 of the second recording medium housing means 30b are arranged in positions opposite to each other relative to the recording medium conveying direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that records an image on a fed recording medium using a liquid discharge head unit.

In an image forming apparatus that records an image on a recording medium fed and conveyed from a paper feeding unit using a liquid discharge head unit, it is necessary to increase the conveying speed of the recording medium in order to increase the productivity (printing speed). In this case, the apparatus is increased in size. As another method, there is a method of narrowing the conveyance interval between the recording media during continuous printing. However, the conveyance interval between the recording media is necessary for the conveyance control. Productivity is not dramatically improved.
In order to eliminate such inconveniences in the image forming apparatus, various proposals have been disclosed in the past for attempting to increase productivity (printing speed) by improving the printing accuracy and reducing the gap between the sheets ( For example, see Patent Document 1).
Japanese Patent Application Laid-Open No. H11-260260 discloses that the detection of the sheet inclination and the sheet attitude control are performed in a state where the sheet is held between a pair of registration rollers, so that the inclination of the sheet does not change after detection.
JP 2006-113281 A

However, in an image forming apparatus using an inkjet system, in many cases, a print head is mounted on a carriage, and printing is performed by scanning in a direction perpendicular to the paper transport direction.
Due to this configuration, the paper must be stopped during printing. To increase productivity (printing speed), increase the paper conveyance speed and carriage scanning speed, or increase the length of the head mounted on the carriage once. There are methods such as increasing the printing width in scanning, but these also increase the size of the apparatus. In particular, when printing in the high image quality (photo) mode, the amount of feed in the paper transport direction is extremely small, so the productivity is significantly reduced.
Inkjet printers are widely used in general households and can be used in various ways, but they are often used for photo printing and New Year's card printing. The photo is also attached to the New Year's card printing, and the high quality mode is selected for printing. Devices specializing in photographic printing have been developed, but even in that case, productivity is not good.
Further, the technique of Patent Document 1 detects skew of a sheet after being fed from a sheet feeding unit and performs skew control and lateral registration position correction in which the sheet posture is controlled while the sheet is held between a pair of registration rollers. It is a technology to do.
Accordingly, an object of the present invention is to improve productivity when printing on photographs and postcards by using two recording medium storage means in consideration of the above-described situation, and when printing on small size paper. It is an object of the present invention to provide an image forming apparatus that improves the performance and does not generate rubbing or jamming.

In order to solve the above problems, the invention described in claim 1 is a recording medium storage unit for recording an image on a fed recording medium using a liquid discharge head unit and storing the recording medium. In the image forming apparatus having at least the first and second recording medium storage units, the first and second recording medium storage units are fixed guides for positioning in a direction perpendicular to the recording medium conveyance direction; A movable guide that faces the fixed guide and moves in a direction that widens or narrows the distance between the fixed guide and the fixed guide of the first recording medium storing means and the fixing of the second recording medium storing means The guide is at a position opposite to the recording medium conveyance direction.
According to a second aspect of the present invention, the image forming apparatus according to the first aspect is characterized in that the two fixed guides are positioned symmetrically with respect to the recording medium conveyance direction.
According to a third aspect of the present invention, there is provided the image forming apparatus according to the first or second aspect, wherein the sheet feeding / conveying operation from the first and second recording medium storing means can be performed simultaneously.
According to a fourth aspect of the present invention, there is provided the image forming apparatus according to the third aspect, wherein the feeding and conveying timings from the first and second recording medium storage units are synchronized.

  According to the present invention, it becomes possible to simultaneously feed a recording medium having a width equal to or less than ½ of the maximum paper passing width in the apparatus from the paper feeding unit as each recording medium storage means. The productivity of the recording medium of ½ or less can be improved, and the fixed guide of the first recording medium storage means and the fixed guide of the second recording medium storage means are opposite to the recording medium conveyance direction. Therefore, the reference position is different, the printed paper is discharged after printing, and the sorting work efficiency of the printed material mixed on the paper discharge tray is increased.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram for explaining the overall configuration of a mechanism portion of an image forming apparatus according to the present invention including a liquid discharge head unit. FIG. 2 is an explanatory plan view of the main part of the apparatus.
Referring to FIGS. 1 and 2, in this image forming apparatus A, a carriage 13 is moved in the main scanning direction by a main guide rod 11 and a sub guide rod 12 horizontally mounted on the left and right main side plates 10A and 10B (FIG. 2). Holds slidably. The carriage 13 is moved and scanned in the direction indicated by an arrow (carriage main scanning direction) via a timing belt by a main scanning motor (not shown).
The carriage 13 includes a plurality of recording heads 14 each composed of a liquid ejection head unit having a plurality of nozzle rows that eject ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). These nozzles (ejection ports) are arranged in a direction crossing the main scanning direction, and are mounted with the ink droplet ejection direction facing downward. The recording head 14 is provided with a nozzle row of each color in which a plurality of nozzles for discharging each droplet of yellow (Y), cyan (C), magenta (M), and black (Bk) are arranged.

Further, the carriage 13 is equipped with a head tank 15 for supplying ink of each color to the recording head 14. The ink tanks 20Y, 20C, 20M, and 20Bk of the respective colors mounted on the cartridge loading section 17 are connected to the head tanks 15 of the respective colors via the supply tubes 16 having the flexibility of the respective colors (in the case where specific ink is not particularly shown). Are shown as ink cartridges 20).
The cartridge loading unit 17 is provided with a supply pump unit 18 which is a liquid feeding unit for feeding ink in the ink cartridge 20. The supply tube 16 is held on the front stay 21 by a holding member 22 in the middle.
On the other hand, from the paper stacking unit 41 as a paper feeding unit for feeding the recording medium (paper) 42 loaded on the paper stacking unit (pressure plate) 41 of the paper feeding cassettes 30a and 30b, which are two recording medium accommodation means. A half-moon-shaped sheet feeding roller 43 that separates and feeds the recording medium 42 one by one and a separation pad 44 made of a material having a large friction coefficient are provided facing the sheet feeding roller 43.

The separation pad 44 is urged toward the sheet feeding roller 43 by elastic means (not shown). In the present embodiment, two such sheet feeding units (sheet feeding cassettes 30a and 30b) are owned, and the recording medium 42 can be fed from either sheet feeding unit.
In order to transport the recording medium 42 fed from the paper feeding unit to the lower side of the recording head 14, a guide member 45 that guides the recording medium 42, a counter roller 46, a transport guide 47, and a tip addition A pressing member 48 having a pressure roller 49 is provided, and a conveying belt 51 is provided as conveying means for electrostatically attracting the fed recording medium 42 to a position facing the recording head 14.
The conveyor belt 51 is an endless belt, and is configured to wrap around the conveyor roller 52 and the tension roller 53 and to circulate in the belt conveyance direction (indicated by the arrow in the sub-scanning direction) shown in FIG. . Further, a charging roller 56 that is a charging unit for charging the surface of the transport belt 51 is provided.

The charging roller 56 is disposed so as to come into contact with the surface layer of the conveyor belt 51 and to rotate following the rotation of the conveyor belt 51. Further, a guide member 57 serving as a platen portion is disposed on the back side of the conveyance belt 51 in correspondence with a printing area by the recording head 14. The conveyance belt 51 rotates in the belt conveyance direction at the same timing as the conveyance roller 52 is rotationally driven by a sub-scanning motor (not shown).
Further, as a paper discharge unit for discharging the recording medium 42 recorded by the recording head 14, a separation claw 61 for separating the recording medium 42 from the conveyance belt 51, a paper discharge roller 62, and a paper discharge roller (spurs). Roller) 63, and a discharge tray 3 is provided obliquely below and to the right of the discharge roller 62 in the figure.
A double-sided paper feeding unit 71 is detachably attached to the back surface of the apparatus body 1. The double-sided paper feeding unit 71 takes in the recording medium 42 returned by the reverse rotation of the conveying belt 51, reverses it, and feeds it again between the counter roller 46 and the conveying belt 51. A manual paper feed unit 72 is provided on the upper surface of the duplex paper feed unit 71.

Further, a maintenance / recovery mechanism 81 including a recovery means for maintaining and recovering the state of the nozzles of the recording head 14 is disposed in the non-printing region on one side in the scanning direction of the carriage 13 (FIG. 2).
The maintenance / recovery mechanism 81 discharges a cap member 82 for collectively capping each nozzle of the recording head 14, a wiper blade 83 which is a blade member for wiping the nozzle surface, and a thickened recording liquid. For this purpose, an empty discharge receptacle 84 for receiving droplets when performing empty discharge for discharging droplets that do not contribute to recording is provided.
Then, the waste liquid of the recording liquid generated by the maintenance / recovery operation by the maintenance / recovery mechanism 81, the ink discharged to the cap member 82, the ink attached to the wiper blade 83 and removed by the wiper cleaner, and the idle ejection to the idle ejection receptacle 84 are discharged. The discharged ink is discharged and stored in a waste liquid tank (not shown).
Further, in the non-printing area on the other side of the scanning direction of the carriage 13, there is an empty space for receiving a liquid droplet when performing an empty discharge for discharging a liquid droplet that does not contribute to recording in order to discharge the recording liquid thickened during recording or the like. An ejection receiver 88 is disposed, and the idle ejection receiver 88 is provided with an opening 89 along the nozzle row direction of the recording head 14.

In the ink jet recording apparatus A configured as described above, the recording medium 42 is separated and fed one by one from the paper feed tray 30, and the recording medium 42 fed substantially vertically upward is guided by the guide member 45 and is conveyed by the conveying belt. 51 and the counter roller 46 are conveyed. Further, the leading end is guided by the conveying guide 47 and pressed against the conveying belt 51 by the leading end pressing roller 49, and the conveying direction is changed by approximately 90 °.
At this time, a positive output and a negative output are alternately applied to the charging roller 56 from an AC supply unit of a control unit (not shown), that is, an alternating voltage is applied. The conveyor belt 51 is an alternating charging voltage pattern, that is, a charging voltage pattern in which plus and minus are alternately charged in a band shape with a predetermined width in the sub-scanning direction that is the circumferential direction.
By feeding the recording medium 42 onto the positively and negatively charged conveying belt 51, the recording medium 42 is electrostatically attracted to the conveying belt 51, and sub-scanning is performed by the circumferential movement of the conveying belt 51. Conveyed in the direction.

Therefore, by driving the recording head 14 in accordance with the image signal while moving the carriage 13, ink droplets are ejected onto the stopped recording medium 42 to record one line. After the recording medium 42 is conveyed by a predetermined amount, the next line is recorded. Upon receiving a recording end signal or a signal that the rear end of the recording medium 42 has reached the recording area, the recording operation is terminated and the recording medium 42 is discharged onto the discharge tray 3.
During printing (recording) standby, the carriage 13 is moved toward the maintenance / recovery mechanism 81, and the ejection surface (nozzle surface) of the recording head 14 is capped by the cap member 82 to keep the nozzle in a wet state. Prevents ejection failure due to recording liquid (ink) drying.
In the state where the ejection surface of the recording head 14 is capped by the cap member 82, the recording liquid is sucked from the nozzle by a suction pump (not shown here) (referred to as nozzle suction or head suction) to increase the viscosity of the recording liquid or bubbles. The recovery operation to discharge is performed. Further, a recovery operation for discharging ink not related to recording is performed before starting recording or during recording. Thereby, the stable ejection performance of the recording head 14 is maintained.

FIG. 3 is a schematic perspective view showing a cassette pull-in mechanism configured on the side of the recording apparatus in order to attach and detach the paper feed cassette to the recording apparatus main body. With reference to FIG. 3, the paper feed cassette 30 which is a recording medium accommodation means and the peripheral portion of the recording apparatus will be described.
The paper cassette 30 is loaded with an inner cassette 31, an outer cassette 32, and recording paper that constitute an outer frame of the paper cassette, and a cassette pressure plate 41 for biasing the recording paper in the direction of the cassette paper feed roller 43. A cassette side guide (movable guide) 34 that is provided on the inner cassette 31 and can be fixed to the horizontal size of any recording paper, and a cassette that is provided on the outer cassette 32 and can be fixed to the vertical size of any recording paper. An end guide 35 is provided.
In this embodiment, a fixed side guide 73 is provided on the left side of the operation surface on the lower right side of the figure, and the recording medium sandwiched between the cassette side guides 34 with these fixed side guides (fixed guides) 73 as a reference. The loading position is regulated.
Further, in the lower part of the recording apparatus, cassette feeding is performed on a right cassette rail 36, a left cassette rail 37, and a cassette pressure plate 41 on which recording sheets are loaded, which guides the attachment and detachment of the sheet feeding cassette 30 to and from the recording apparatus main body 1 (FIG. 1). A right pressure plate spring 38, a left pressure plate spring 39 for applying a biasing force in the direction of the paper roller 43, a right pressure plate arm 64 that moves up and down by the biasing force of the right pressure plate spring 38, and a left pressure plate spring 39. The left pressure plate arm 65 that moves up and down in response to the urging force is provided.

Abutting portions 41 a and 41 b of the cassette pressure plate 41 are held on the right pressure plate arm 64 and the left pressure plate arm 65 so as to be placed thereon. A right pickup cam 66 and a left pickup cam 67 that control the vertical movement of the right pressure plate arm 64 and the left pressure plate arm 65 are attached to the left and right shaft ends of the cassette paper feed roller 43.
As a result, when the cassette paper feed roller 43 rotates, the right pressure plate arm 64 and the left pressure plate arm 65 move up and down, and the cassette pressure plate 41 is urged toward the cassette paper feed roller 43, thereby supplying the recording medium. Paper.
Further, a cassette pulling lever 68 and a pulling spring 69 are provided on the side of the recording apparatus, thereby constituting a cassette pulling mechanism. In FIG. 3, the cassette pull-in mechanism is in a state where the paper feed cassette 30 is not pulled into the recording apparatus main body 1 (FIG. 1).

When the paper feeding cassette 30 is pulled into the recording apparatus main body 1 from the state of FIG. 3, the cassette pulling lever 68 moves along the left cassette rail 37, and the end of the cassette pulling lever 68 is moved to the end portion 37 a of the left cassette rail 37. The portion 68a contacts to fix the paper feed cassette 30.
In this configuration, the cassette pull-in lever 68 is formed on the side surface of the paper feed cassette 30. Therefore, the height of the recording apparatus main body 1 can be kept lower than when the cassette pull-in lever 68 is configured below the paper feed cassette 30.
Further, the carriage 13 (see FIG. 2) is provided with a point at which a pulling force by the cassette pulling lever 68 acts and an abutting portion of the paper feeding cassette 30 (not shown) in front of the paper feeding cassette 30 to the recording apparatus main body 1. In the main scanning direction in which 2) scans, it is desirable to make the same direction as possible.
In this way, the tilt component of the paper feed cassette 30 with respect to the recording apparatus main body 1 can be suppressed. further. The cassette pull-in lever 68 is preferably provided on the reference surface side of the recording medium in the paper feed cassette 30.

In an image forming apparatus, the actual maximum sheet passing width is set larger than the maximum sheet width of a sheet that is a recording medium allowed for the image forming apparatus. Therefore, the above-described paper feed cassette is used as two recording medium accommodating means, and in this case, the fixing guides of the respective paper feed cassettes are provided symmetrically.
In other words, a paper cassette in which each member arrangement in the configuration of the paper cassette of FIG. 3 is symmetric is used, the maximum paper width is set to the maximum paper passing width end, and the paper feed port, that is, the paper feed, By sequentially changing the paper cassette, the printing speed (productivity) can be improved.

FIG. 4 is a schematic view showing a conveyance state of a sheet as a recording medium from two recording medium accommodating means. As shown in FIG. 4, the printed materials mixed on the paper discharge tray are sorted to the left and right with respect to the paper conveyance direction, and the mixed work of the mixed printed materials can be easily performed.
In this case, the printed material mixed on the paper discharge tray becomes a blackish printed material and a whiteish printed material due to the difference in the paper feed port from the two recording medium accommodating means which are paper feed cassettes, and several sheets are output. In this case, as shown in the lower part of the figure, black and white bands are alternately overlapped.
Further, with the above-described configuration, the recording medium stacking reference is bilaterally symmetric in each of the two paper supply units (recording medium accommodating means), and recording is performed with a recording paper width of ½ or less of the maximum sheet passing width in this apparatus. Media can be passed simultaneously from the respective paper feed units, and the productivity of a recording medium having a width equal to or less than ½ of the maximum paper passing width can be improved.

FIG. 5 is a schematic diagram for explaining a case where a deviation occurs in the sub-scanning direction during conveyance of the recording medium. FIG. 6 is a schematic diagram for explaining a case where there is no deviation in the sub-scanning direction during conveyance of the recording medium. It is desirable that the recording medium is immediately discharged from the paper discharge unit after printing is completed.
As shown in FIG. 5, when the rear end of the recording medium P1 remains within the scanning movable range of the carriage 13 (FIG. 2), the recording medium P1 and the carriage 13 interfere with each other due to the floating and undulation of the recording medium P1. Causes rubbing and jamming. Further, as the water content of the ink penetrates into the recording medium P1, the undulation tends to increase.
When the positions of the recording media P1 and P2 fed from the two paper feeding units in the transport direction (sub-scanning direction) are shifted, the recording medium P1 that has finished printing first moves to the recording medium P2 that has been delayed. The paper is not discharged until the printing is finished, and when the amount of positional deviation is large, there is a possibility of causing rubbing or jamming.
By synchronizing the timing of paper feeding from the two paper feeding units (first and second recording medium accommodating means) and aligning the positions of the recording media fed from the respective paper feeding units in the transport direction ( 6), it becomes possible to discharge at the same time, and it becomes possible to prevent rubbing and jamming. Further, the two recording media are transported at the same timing, and the productivity is twice that of the conventional one.
The timing to synchronize from the difference in the transport path from the two paper feeding units to the printing area is unique to the apparatus. Therefore, the control time of the synchronization timing is obtained from simulations and experiments on individual devices.

The description of the embodiment of the present invention is an image forming apparatus using an ink jet system, but it can also be applied to an image forming apparatus such as electrophotography, and a recording medium containing means installed in two stages below the main body is provided. Although the explanation was made with reference to this, it does not stick to the installation position of the recording medium accommodation means. Recording medium storage means (paper feeding means) installed on the lower operation surface side of the main body and recording medium storage means installed on the rear side of the main body may be used. You can use it.
When three or more recording medium accommodating means are provided, the fixed side guide positions of other paper feeding means may be symmetrical with respect to the paper feeding means used as the main, and the combination thereof is not particular.
As described above, since the image forming apparatus A includes the recording head 14 including a highly reliable liquid discharge head unit (or liquid discharge head), it is possible to form a high-quality image with no edge deviation.
In the above-described embodiment, the printer configuration has been described as the image forming apparatus according to the present invention. However, the present invention is not limited to this, and can be applied to an image forming apparatus such as a printer / facsimile / multifunction machine. Further, the present invention can also be applied to an image forming apparatus using a recording liquid other than ink, a fixing processing liquid, a DNA sample, a resist or the like, and other apparatuses for ejecting droplets.

1 is a schematic configuration diagram illustrating an overall configuration of a mechanism unit of an image forming apparatus according to the present invention that includes a liquid ejection head unit. It is principal part plane explanatory drawing of the apparatus. FIG. 6 is a schematic perspective view showing a cassette pulling mechanism configured on the side of the recording apparatus for attaching and detaching a paper feed cassette to and from the recording apparatus main body. It is the schematic which shows the conveyance state of the paper which is a recording medium from two recording medium accommodation means. FIG. 10 is a schematic diagram for explaining a case where a shift occurs in the sub-scanning direction during recording medium conveyance. FIG. 10 is a schematic diagram illustrating a case where there is no deviation in the sub-scanning direction during recording medium conveyance.

Explanation of symbols

  A: Image forming apparatus (inkjet recording apparatus, printer), 1 recording apparatus main body, 13 carriage, 14 liquid ejection head unit (recording head), 30 recording medium storage means (paper feeding unit, paper feeding cassette), 30a first recording Medium storage means (paper feed section, paper feed cassette), 30b Second recording medium storage means (paper feed section, paper feed cassette), 34 movable guide (cassette side guide), 73 fixed guide (fixed side guide) P1 first Recording medium from one recording medium storage means, P2 Recording medium from second recording medium storage means

Claims (4)

In an image forming apparatus having at least first and second recording medium storage means as recording medium storage means for recording an image on a fed recording medium using a liquid discharge head unit and storing the recording medium. ,
The first and second recording medium storage units move in a direction that widens and narrows the space between the fixed guide and the fixed guide that are positioned in a direction orthogonal to the recording medium conveyance direction, and that faces the fixed guide. And a fixed guide of the first recording medium storage means and a fixed guide of the second recording medium storage means are in positions opposite to the recording medium conveyance direction. An image forming apparatus.   The image forming apparatus according to claim 1, wherein the two fixed guides are positioned symmetrically with respect to a recording medium conveyance direction.   3. The image forming apparatus according to claim 1, wherein the sheet feeding and conveying operations from the first and second recording medium storage units can be performed simultaneously.   4. The image forming apparatus according to claim 3, wherein timings of feeding and feeding from the first and second recording medium storage units are synchronized.

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