JP5428778B2 - Duplex printing device - Google Patents

Description

  The present invention relates to a duplex printing apparatus that performs printing on both sides of a sheet.

  As a conventional double-sided printing device, the surface-printed paper is stopped by the moving guide plate, clamped by the clamping claw, moved to a position where it can be sufficiently transported by the refeed unit, and then the surface-printed paper is released. In some cases, the paper is reversed so that it can be re-fed to the printing means (see, for example, Patent Document 1).

In addition, there is a printing apparatus in which a discharge member of the printing apparatus includes a buffer member that cushions an impact caused by a collision of the discharged printing apparatus, and the buffer member is fixed so that a collision surface of the printing paper is inclined downward. (For example, refer to Patent Document 2).

  In addition, as a paper stacking device, a rear end fence serving as a paper alignment reference wall is provided on the discharge side of the paper discharge tray, and a paper stopper member is provided so as to come into contact with the front end in the paper discharge direction of the paper stacked on the paper discharge tray. Some are provided (see, for example, Patent Document 3).

  However, in the above-mentioned Japanese Patent Application Laid-Open No. 2004-228561, in order to obtain the image contamination countermeasure immediately after printing and the position accuracy and angle accuracy necessary for feeding the paper again for the front surface printed paper, FIG. The paper collided with the moving guide plate as shown, and the paper was positioned (registered) / tilted (skew) and moved to a position where it could be conveyed by the refeed unit. For this reason, noise was generated by the collision.

  Further, when the paper P collides, as shown in FIG. 20, the paper P resonates simultaneously with the collision, and the noise is increased.

  Further, the above-mentioned Patent Documents 2 and 3 are noise countermeasures when paper is discharged, and when high accuracy such as resist and skew for performing subsequent paper conveyance for double-sided printing is not required. It was what was used. That is, it has not been considered to be applied to applications requiring basic performance such as skew and resist for performing double-sided printing.

  The present invention has been made in view of such a situation, and double-sided printing that can suppress noise generation without degrading basic performance such as high-precision paper positioning necessary for performing double-sided printing. An object is to provide an apparatus.

In order to achieve such an object, a duplex printing apparatus according to the present invention includes a printing unit that forms an image on a sheet, a front surface printed sheet on which an image is formed, and the front surface printed sheet is turned upside down. A re-feeding unit that re-feeds the printing unit toward the printing unit, and the front-side printed sheet fed from the printing unit is sandwiched at a first position near the printing unit, and then the first position A sheet nipping unit for releasing nipping of the surface-printed sheet at a second position near the upstream side of the lower sheet refeeding unit, and the sheet nipping between the first position and the second position. Moving means for reciprocating the means, and the paper clamping means includes a paper colliding surface for colliding the front surface printed paper fed from the printing means, and a paper placement for mounting the front surface printed paper And the paper collision surface The sheet is provided so as to be inclined at a predetermined angle with respect to the vertical plane with respect to the paper entry direction, and a predetermined space is established between the paper collision surface and the paper placement surface, and the front end of the surface-printed paper is formed in the space. The sheet is provided so as to be able to enter, and is provided so that the surface-printed sheet is deformed in contact with the sheet collision surface and the sheet placing surface by the entry .

  As described above, according to the present invention, it is possible to suppress the generation of noise without degrading the basic performance required for performing double-sided printing, such as high-precision paper positioning.

It is a longitudinal cross-sectional view which shows the structural example of the double-sided printing apparatus as each embodiment of this invention. It is sectional drawing which shows the movement guide plate as 1st Embodiment. It is a figure which shows the experimental result about the relationship between the collision angle (theta) by the inclination board 17, and various performances. It is a figure which shows the noise measurement data by the double-sided printing apparatus of a prior art. It is a figure which shows the comparison data of the collision sound peak value by the prior art and the double-sided printing apparatus of this embodiment. It is a perspective view which shows the movement guide plate as 2nd Embodiment. It is sectional drawing which shows the movement guide plate as 2nd Embodiment. It is a perspective view which shows the state which the paper collided with the movement guide plate as 2nd Embodiment. It is a longitudinal cross-sectional view which shows the state which the paper collided with this movement guide plate. FIG. 6 is a cross-sectional view of a state where a sheet collides with the moving guide plate as viewed from the sheet traveling direction. It is a perspective view which shows the movement guide plate as 3rd Embodiment. It is sectional drawing which shows the movement guide plate as 3rd Embodiment. It is a figure which shows the operation example around the movement guide plate of 3rd Embodiment. It is the perspective view and longitudinal cross-sectional view which show the movement guide plate as a modification of 3rd Embodiment. It is a perspective view which shows the movement guide plate as 4th Embodiment. It is sectional drawing which shows the movement guide plate as 4th Embodiment. It is a perspective view which shows the movement guide plate as a modification of 4th Embodiment. It is sectional drawing which shows the movement guide plate as a modification of 4th Embodiment. It is sectional drawing which shows the conventional movement guide plate. It is a perspective view which shows the propagation of the collision sound by the conventional moving guide plate.

Next, an embodiment to which a duplex printing apparatus according to the present invention is applied will be described in detail with reference to the drawings.
Each embodiment of the present invention exemplifies a suitable one that can reduce noise in the refeeding operation in the duplex printing apparatus.

[First Embodiment]
First, a first embodiment of the present embodiment will be described with reference to FIGS.
In the present embodiment, as shown in FIG. 1, a stencil printing apparatus 1 as a printing apparatus includes a scanner unit 2, a plate making unit 3, a plate discharging unit 4, a paper feeding device 5, an image forming unit 6, and a paper ejection suction conveyance unit 7. The paper discharge unit 8, the air knife unit 9, and the refeed unit 10 are mainly configured. The scanner unit 2 is a part that reads a set original as image information. The plate making unit 3 writes the read image information on a master (stencil sheet) M to carry out plate making, conveys the master M thus made to the printing drum 11 of the image forming unit 6, and places the master M on the outer peripheral surface of the printing drum 11. It is the part to wrap.
The plate removal unit 4 is a portion that peels off the master M wound around the outer peripheral surface of the printing drum 11 that is no longer necessary after the printing is finished, and stocks the discharged master M.

  The present embodiment has main features in the movement guide plate 12 of the refeed unit 10 and its function is as follows.

  First, the paper feeding device 5 separates the set paper P into one sheet and conveys it to the image forming unit 6 (P1 position). When double-sided printing is performed on the paper on which the back surface is printed, the paper is guided to the P2 position by the switching claw 13 at the front end of the paper discharge suction conveyance unit 7.

The moving guide plate 12 waits for a sheet fed from the image forming unit 6 by moving to the vicinity of the press roller 14. When the paper P is inserted into the movement guide plate 12, the clamp pawl 15 attached to the movement guide plate 12 clamps (holds) the paper P.
Thereafter, the moving guide plate 12 moves in a direction approaching the paper discharge unit 8 to release the clamped state of the paper P. When the released paper is conveyed to the P3 position by the refeed unit 16, the paper P is sent again to the image forming unit 6 by the press roller 14 and the surface is printed. When the front side printing is performed, the sheet is discharged to the sheet discharge unit 8 by the sheet discharge suction conveyance unit 7.

  As shown in FIG. 2, in this embodiment, an inclined plate (paper collision surface) 17 is attached to the moving guide plate 12, and the paper P sent out from the image forming unit 6 collides with the inclined plate 17 to move. The impact force when the movement is stopped by the guide plate 12 is reduced. As a result, noise during a collision can be reduced.

  If a cushion material made of urethane or the like is attached to the inclined plate 17, a sound reduction effect can be expected. In this case, it is preferable to prevent wear by a SUS plate material or a PET sheet where the paper end faces collide. Details will be described later as a second embodiment.

  As shown in FIG. 3, the collision angle θ by the inclined plate 17 is more effective for noise as the angle θ is smaller. However, the paper conveyance jam tends to be worse when the angle is small. Therefore, 60 ° to 80 ° is desirable, and if the angle is less than 60 °, the paper is likely to sink and jam easily occurs.

  Further, when the impact when the collision with the moving guide plate 12 is eased by the inclined plate 17, the rebound is reduced, resulting in less skew of the paper P (paper inclination) and better resist (printing position accuracy). Become.

As described above, the first embodiment described above has the following features.
Relative to the plate cylinder and the plate cylinder on which the divided plate-making master is formed, in which the first plate-making image and the second plate-making image are formed side by side along the rotation direction of the plate cylinder. A printing unit having a releasable pressing means; a paper feeding unit that feeds paper toward the printing unit; a paper discharge unit that discharges printed paper printed by the printing unit; and The surface printed paper on which the printed image is formed on the surface corresponding to the first plate-making image or the second plate-making image is temporarily held, and then the surface-printed paper is sent toward the pressing means. A refeed unit that reverses by the pressing means and refeeds toward the printing unit, and a front end of the front surface printed paper fed from the printing unit is sandwiched near a first position near the printing unit. The second position in the vicinity of the upstream side of the re-feeding unit lower than the first position. The sheet clamping means for opening the front end of the surface printed sheet, the moving means for reciprocating the sheet clamping means between the first position and the second position, and the sheet clamping means occupy the first position. The paper holding means is opened once, and then operated to hold the leading edge of the surface printed paper. When the paper holding means occupies the second position, the paper holding means is And an operation timing control means that operates to open the front end of the surface-printed paper, and a switching means that guides the paper that has passed through the printing section to the paper clamping means or the paper discharge section. A double-sided printing apparatus capable of printing on both sides of a sheet with one rotation of a plate cylinder, characterized in that the sheet-clamping surface of the sheet-clamping means is inclined and includes means for reducing sheet-impact sound. And

  For this reason, according to the first embodiment described above, noise is reduced without any deterioration in basic performance such as high accuracy such as resist and skew necessary for performing double-sided printing, and anti-image contamination immediately after surface printing. Can be lowered.

More specifically, a conventional one drum which can easily and inexpensively obtain a printed material with good image quality without unevenness in printed image density or difference in printed image density during double-sided printing, and can suppress an increase in installation space. 1-pressing means Double-sided printing device that is simpler than the double-sided printing method of double-sided printing system, that is, the paper clamping means and the moving means are provided, so even if the paper is weak, the leading edge of the paper can be inserted without resistance. It is possible to provide a novel double-sided printing device that can reliably and satisfactorily hold the front end of the surface-printed paper and eliminates the need for refeed storage in the conventional double-sided printing device, Preventing the occurrence of rubbing stains on the surface printed paper by preventing contact between the surface printed paper fed from the printing section and the surface printed paper in the refeed section This makes it possible to prevent jamming of the surface-printed paper, and it can be transported well in a stable state without meandering or skewing of the surface-printed paper. It is possible to prevent the printed image from being tilted or the resist from being deteriorated due to the tilt or the like.
Furthermore, since the surface of the inclined plate 17 is made of SUS or the like, there is no problem in durability even if the collision is repeated on the sheet end surface.

The noise reduction effect is shown in FIGS.
FIG. 4 shows data obtained by passing A4 size 90k paper at the 5th speed (120 cpm) with a conventional double-sided printing apparatus and measuring noise on the paper discharge side. The horizontal axis represents time, the vertical axis represents frequency, and the sound The strengths are color-coded. FIG. 5 shows the peak value of the collision sound shown in FIG. 4 and shows a comparison between the double-sided printing apparatus of the prior art and the apparatus to which this embodiment is applied. As a result, an effect of about 10 dB was confirmed at the peak portion.

  The principle of sound reduction is that the collision sound is generated when the end face of the sheet P collides with the moving guide plate 12 as shown in FIG. In the present embodiment, by providing the inclined plate 17 inclined by a predetermined angle (90 ° −θ) with respect to the vertical plane with respect to the paper entering direction, it is possible to reduce an increase in impact noise caused by the paper P.

[Second Embodiment]
Next, a second embodiment of the present embodiment will be described with reference to FIGS.
In this embodiment, as shown in FIGS. 6 and 7, a plurality of inclined plates 17 (four in the example of FIG. 6) are attached to the moving guide plate 12, and a gap of 1 to 3 mm is formed around the periphery. Further, the inclined plate 17 has a configuration in which a cushion material 18 and a wear-resistant plate 19 are attached.
FIG. 7 shows a structure for releasing the impact force by the moving guide plate of this embodiment.

  The angle of the inclined plate 17 is desirably θ = 60 ° to 80 ° as in the first embodiment described above. The cushion material 18 is preferably a urethane cushion material having a thickness of about 0.01 MPa at a 25% compression load, a thickness of about t1, excellent shock absorption, low temperature dependence, and considering durability.

  Although the wear prevention material 19 can be a PET material or the like, it is preferable to add an R to the corner of the collision surface with the paper P, and therefore, a sheet metal such as SUSt 0.1 to 0.3 is recommended. In the case of a printing machine with a paper speed of about 1000 mm / sec, about R2 to 3 mm is desirable.

A state in which the sheet collides with the moving guide plate 12 is shown in FIGS.
As shown in FIG. 8, by setting a space of several millimeters around the inclined surface with the cushion and the periphery thereof, the end portion enters the space at the time of paper collision. As a result, the primary collision sound can be reduced.

Further, since the leading edge of the sheet enters the space and the leading edge of the sheet comes into contact with the lower side of the inclined plate 17 and the sheet placement surface of the moving guide plate 12, the sheet is slightly deformed. The typical reverberation is suppressed.
9 and 10 are cross-sectional views showing a state in which the leading edge of the paper has entered.
As shown in FIG. 10, the leading edge of the paper has a wave shape, and as shown in FIG.

  In this way, the leading edge of the sheet enters the space between the lower side of the inclined plate 17 and the sheet placement surface (bottom surface) of the moving guide plate 12, and the leading end of the sheet is on the lower side of the inclined plate 17 and the sheet of the moving guide plate 12. Propagation of the sound of the paper is suppressed by abutting each of the placement surfaces.

As described above, the above-described second embodiment has the following features.
In the double-sided printing apparatus according to the first embodiment described above, the paper collision surface of the paper clamping unit is inclined, and the inclined surface has several spaces and a space of several millimeters around the inclined surface, so that the sound of the paper is propagated. And a means for reducing the collision sound.

  For this reason, according to the second embodiment described above, by installing a predetermined number of the inclined plates 17 and providing a space around the inclined plates 17, the paper P is deformed as shown in FIGS. Can be reduced. For this reason, it is possible to reduce the collision noise without degrading the basic performance such as rubbing dirt, skew, and resist.

[Third Embodiment]
Next, a third embodiment of the present embodiment will be described with reference to FIGS.
In this embodiment, as shown in FIG. 11 and FIG. 12, when the mute flap 20 is attached (not fixed) to the clamp claw shaft 21 and the paper P enters and collides with the moving guide plate 12, The silencer flap 20 holds down the surface of the paper P and minimizes vibrations and noise transmitted by the paper P itself.

  The shape of the muffler flap 20 may be a strip shape. As the set load, it is preferable to hold the paper P with a load of about 100 gr.

The operation of the third embodiment will be described in detail with reference to FIG.
The silencer flap 20 is urged in a direction in which the silencer flap 20 abuts against the sheet placement surface of the movement guide plate 12 when there is no sheet. When the paper is fed from the printing drum 11, it moves with the lower side (free end side) of the silencer flap 20 while the leading edge of the paper hits the inclined surface of the silencer flap 20 (a surface inclined at a predetermined angle from the vertical plane with respect to the paper entry direction). Propagation of the collision sound of the sheet is suppressed by entering between the sheet placement surfaces of the guide plate 12 and the silencing flap 20 pressing the leading edge of the sheet by the above urging.

At the time of receiving the paper in FIG. 13A, when the paper collides with the silencer flap 20, the silencer flap 20 can suppress the margin at the leading edge, so that the secondary paper echo sound at the time of the collision can be suppressed.
Further, if a cushion is installed on the vertical wall surface of the moving guide plate 12 where the paper end face collides, the primary sound at the time of the collision can be lowered.

  Then, after the moving guide plate 12 is moved to the vicinity of the refeed unit 16 according to FIG. 13B, the holding by the flap is released at the time of refeeding in FIG. 13C. In this state, only the paper is fed again by the belt feeding of the refeed UNIT.

As described above, in this embodiment, the spring 22 is provided between the clamp claw shaft 21 and the flap 20, and the paper P is urged by the spring 22 in the direction of the paper placement surface when entering and transporting the paper P. Try to hold it down.
At the position where the clamp pawl 15 opens the paper P, the lever 20 ′ which is a part of the flap 20 is released by a protrusion (not shown) attached to the main body of the printing machine, and the paper is conveyed by the refeed unit 10 To avoid resistance.

As described above, the above-described third embodiment has the following features.
In the double-sided printing apparatus according to the first embodiment described above, the paper collision surface of the paper clamping means is inclined, and a wide range of a few millimeters from the front end of the paper is clamped over a wide range, so that the propagation of the sound of the paper and the collision sound It is characterized by having means for reducing the above.

  Therefore, according to the third embodiment described above, although the sound reduction effect is inferior by several dB compared to the first embodiment described above, as in the first embodiment described above, rubbing dirt, skew, resist, etc. Without degrading the basic performance at all, the basic performance remains the same as the current equipment, and the collision sound can be reduced.

[Modification of Third Embodiment]
FIG. 14 shows a modification of the third embodiment.
In this modified example, a flexible mylar is used instead of the configuration in which the silencer flap 20 is biased by a spring as in the configuration example described above. Although the force for pressing the front end of the paper is weaker than the configuration of FIG. 12 described above, deformation such as turning of the front end of the paper when receiving the paper can be suppressed.

In this modified example, as shown in FIG. 14, the Mylar sheet can suppress deformation such as sheet edge turning when receiving the sheet, and the sheet edge can collide with the maximum point of the cushion silencing effect. In addition, it is possible to suppress the secondary reverberation sound of the collision sound.
Further, as in the above-described operation example of FIG. 13, the Mylar sheet may be configured to move according to the respective states at the time of paper reception, paper conveyance, and paper re-feed.

  Further, the material is not limited to the Mylar sheet, and various materials may be used as long as the material is a sheet-like soft material that does not cause paper conveyance resistance.

[Fourth Embodiment]
Next, a fourth embodiment of the present embodiment will be described with reference to FIGS.
In this embodiment, as shown in FIGS. 15 and 16, one end of the elastic plate 23 is fixed to the lower part of the moving guide plate 12 (by double-sided tape / caulking or the like), the moving guide plate 12 is sandwiched, Attach the plate 24 to the other end.

  When the paper P enters, it moves along the plate 24 and collides with a paper collision surface provided at the end of the telescopic plate 23 opposite to the fixed end. At this time, the spring portion of the telescopic plate 23 absorbs the impact and reduces the collision sound. The extendable plate 23 may be a SUS plate spring or a resin plate such as PET, and the extendable portion may be a coil spring. The load setting is desirably 300 to 400 gr (total of all the extendable plates 23) when the paper P enters.

  Further, the location where the paper P collides with the extendable plate 23 is preferably provided with an angle of several tens of degrees so that the paper P can be easily held. In FIG. 15, four sets of the extendable plate 23 and the plate 24 are attached, but there is no problem even if 1 to 6 sets are attached.

As described above, the above-described fourth embodiment has the following features.
In the double-sided printing apparatus according to the first embodiment described above, the sheet collision surface of the sheet clamping unit is inclined at a predetermined angle with respect to the vertical plane with respect to the sheet entry direction, and the collision surface is a spring independent of the sheet clamping unit. And a means for reducing a collision sound when the paper collides.

  For this reason, according to the above-described fourth embodiment, although the sound reduction effect is inferior by several dB compared to the above-described first embodiment, like the above-described first embodiment, rubbing dirt, skew, resist, etc. Without degrading the basic performance at all, the basic performance remains the same as the current equipment, and the collision sound can be reduced.

[Modification of Fourth Embodiment]
17 and 18 show a modification of the fourth embodiment.
In this modification, the slide plate 26 is attached to the upper part of the moving guide plate 12, and the spring 26 is attached to the lower part of the moving guide plate 12, so that the slide plate 25 is not easily detached.

  Even in the configuration of this modification, the same effects as those of the configuration example of the fourth embodiment described above can be obtained.

[About each embodiment]
Each of the above-described embodiments is a preferred embodiment of the present invention, and the present invention is not limited to this, and various modifications can be made based on the technical idea of the present invention.

DESCRIPTION OF SYMBOLS 1 Stencil printing device 2 Scanner part 3 Plate making part 4 Ejection part 5 Paper feeder 6 Image formation part 7 Paper discharge adsorption conveyance part 8 Paper discharge part 9 Air knife part 10 Refeed part 11 Printing drum 12 Moving guide plate 13 Switching claw 14 Press roller 15 Clamp claw 16 Refeed unit

JP 2005-125716 A Japanese Patent No. 3691325 Japanese Patent No. 3744704

Claims (2)

Printing means for forming an image on paper;
A sheet refeeding unit that holds a surface printed sheet on which an image is formed on the surface, reverses the sheet with the surface printed, and refeeds the sheet toward the printing unit;
After the front surface printed paper fed from the printing means is sandwiched at a first position near the printing means, at a second position near the upstream side of the refeeding means lower than the first position. Paper nipping means for releasing nipping of the front surface printed paper;
Moving means for reciprocating the sheet clamping means between the first position and the second position;
With
The paper clamping means is
A paper collision surface for colliding the front surface printed paper sent out from the printing means;
A paper mounting surface for receiving the front surface printed paper;
With
The paper collision surface is provided to be inclined at a predetermined angle with respect to a vertical surface with respect to the paper entry direction,
A predetermined space is established between the paper collision surface and the paper placement surface,
The space is provided such that a front end of the surface-printed paper can enter, and the surface-printed paper is provided in contact with the paper collision surface and the paper placement surface to be deformed by the entry. A double-sided printing apparatus characterized by that. The paper collision surface includes a cushion material and a wear-resistant plate,
  The double-sided printing apparatus according to claim 1, wherein the wear-resistant plate is disposed on a side of the paper collision surface that collides with the surface-printed paper.

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