JP2011194877A - Noise reduction structure for printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a noise reduction structure of the inner part of a printer without generating dust like an acoustic absorption member.SOLUTION: A perforated board having many penetrated holes (for example a bottom board 5 (a tray under-side perforated board)) is arranged around a paper-feeding tray 2 so as to enter acoustic waves generated from a paper-feeding tray 2 part and the like through the penetrated holes. A board member (for example a bottom board 15 (a tray under-side board member)) that blocks air passage is arranged so as to face the perforated board (for example the bottom board 5 (the tray under-side perforated board)). A side part opening between the perforated board (for example the bottom board 5 (the tray under-side perforated board)) and the board member (for example the bottom board 15 (the tray under-side board member)) that blocks air passage is shut.

Description

  The present invention relates to a noise reduction structure for a printing machine, such as a printer, a copying machine, a facsimile machine, etc., in which the object to be printed is paper.

  In order to work in a comfortable environment, it is necessary to obtain a quiet indoor environment as one means. In order to obtain a quiet indoor environment, it is necessary to take measures to reduce the noise of printers installed in rooms such as printers, copiers, and facsimiles. As a technique related to measures for reducing noise in a printing press, for example, there are techniques described in Patent Documents 1 and 2 below.

  In Patent Document 1, a sound insulation plate that covers the gap between the bottom of the apparatus (printing machine) and the installation floor of the apparatus is attached to the outer wall of the apparatus, and the sound leakage (noise) from the apparatus (printing machine) is caused by the sound insulation board. ) Is described.

  Further, in Patent Document 2, a sound absorbing member is attached to a recess provided in a case member at the top of the paper feed tray, and this sound absorbing member reduces leakage sound (noise) from the gap between the case member and the paper feed tray portion. The technology is described.

JP 2001-356657 A JP-A-5-138987

  However, with the technique described in Patent Document 1 (measures for reducing noise using a sound insulation plate), when moving the apparatus (printing machine), it is necessary to remove and reattach the sound insulation plate. Further, since it is necessary to cover the entire outer periphery of the lower part of the apparatus (printing machine) with a sound insulation plate, the sound insulation plate is a large member. Furthermore, since the sound insulation board directly touches the human eye, it is necessary to make the sound insulation board excellent in design. As a result, the manufacturing cost of the printing machine increases.

  On the other hand, in the technique described in Patent Document 2 (measures for reducing noise by a sound absorbing member attached to a recess), the sound absorbing member is not very effective for low frequency components. In addition, when urethane or glass wool is used as the sound absorbing member, dust may be generated. When dust is generated, the dust may adhere to the paper that is the object to be printed, which may deteriorate the printing resolution or damage the printing unit of the printing press.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a noise reduction structure inside a printing press that does not generate dust like a sound absorbing member.

  As a result of intensive studies to achieve the above object, the inventors of the present invention have made the peripheral wall of the paper feed tray a perforated plate, and the perforated plate and the air layer behind the perforated plate are particularly loud among the noises of the printing press. Noises that leaked from the gap between the bottom of the printing press and the installation floor (paper collision / rubbing noise, drive motor drive noise, etc.) were reduced. Based on this finding, the present invention has been completed.

  That is, the present invention relates to a noise reduction structure for a printing press in which the object to be printed is paper, and a perforated plate having a large number of through holes is provided in the printing press so that sound waves generated inside the printing press enter from the through holes. Arranged around the internal paper feed tray, ventilation path, or paper conveyance path, the plate member that blocks the passage of air is arranged in the printing machine so as to face the perforated plate, the perforated plate and the plate A noise reduction structure for a printing press, wherein an air layer is formed between the member and the member.

  According to this configuration, the perforated plate arranged around the paper feed tray, ventilation path, or paper transport path inside the printing press, the plate member that blocks the passage of air, and the back of the perforated plate defined by the perforated plate The air layer of the printer can reduce the noise of the printing press that propagates in the air (paper collision / rubbing noise, drive motor drive noise, etc.) (paper collision / rubbing noise, hoisting, etc.) Printing machine noise such as motor gear drive noise can be prevented from leaking outside). Moreover, since a perforated plate is used, dust is not generated like a sound absorbing member. That is, a noise reduction structure inside the printing press that does not generate dust like the sound absorbing member can be obtained.

  Moreover, if the members (bottom plate, side plate, etc.) constituting the printing press are used as plate members that block the passage of air, a drastic design change of the printing press can be avoided. Furthermore, when the members (bottom plate, side plate, etc.) constituting the printing press have a double structure having a space inside, the inner member of the double structure member (plate) should be used as a porous plate. Thus, a drastic design change of the printing press can be further avoided.

  In the present invention, a tray lower surface side porous plate, which is one of the porous plates, is disposed below the paper feed tray so as to face the paper feed tray, and the plate member is disposed below the tray lower surface side porous plate. It is preferable that a tray lower surface side plate member which is one of the above is disposed.

  According to this configuration, it is particularly easy to reduce paper collision noise and rubbing noise when being fed out from the paper feed tray.

  Further, in the present invention, a paper winding motor gear is disposed inside the printing machine and around the paper feed tray, and the first motor gear side which is one of the perforated plates so as to face the paper winding motor gear A perforated plate is disposed, and a first motor gear side plate member, which is one of the plate members, is disposed so as to sandwich the first motor gear side perforated plate with the paper winding motor gear, and faces the paper feed tray. A second motor gear side perforated plate, which is one of the perforated plates, is arranged as described above, and a second motor gear which is one of the plate members so as to sandwich the second motor gear side perforated plate with the paper feed tray. A side plate member is disposed, and the first motor gear side porous plate or the first motor gear side plate member and the second motor gear side porous plate or the second motor gear side plate member are connected at ends. It is preferable.

  According to this configuration, it is possible to reduce both the collision noise and rubbing sound of the paper and the driving noise of the paper winding motor gear when it is fed out from the paper feed tray. In addition, there is often a long space beside the paper winding motor gear in a direction away from the paper winding motor gear. That is, according to this configuration, it is easy to reduce the driving sound of the paper winding motor gear (using the long space beside the paper winding motor gear, the driving sound in the low frequency region (for example, 400 Hz region) of the paper winding motor gear is also reduced. Can be reduced). Here, the motor gear refers to a motor and a set of gears, but when the motor and the gear are separately arranged, only one of them may be a noise reduction target.

  Furthermore, in this invention, the paper conveyance path | route side porous board which is one of the said perforated boards is arrange | positioned under the paper conveyance path | route inside a printing press, and the said plate member is below the said paper conveyance path | route side porous board by one of the said plate members. It is preferable that a certain paper conveyance path side plate member is disposed.

  According to this configuration, it is particularly easy to reduce paper collision noise and rubbing noise from the paper conveyance path.

  Furthermore, in this invention, the tray upper surface side porous plate which is one of the said porous plates is arrange | positioned above the said paper feed tray so as to oppose the said paper feed tray, and the said plate member above the said tray upper surface side porous plate It is preferable that a tray upper surface side plate member which is one of the above is disposed.

  According to this configuration, it is particularly easy to reduce paper collision noise and rubbing noise when being fed out from the paper feed tray.

  Further, in the present invention, a motor gear for paper winding is arranged inside the printing machine and around the paper feed tray, and a motor gear porous plate which is one of the porous plates so as to surround the paper winding motor gear Preferably, a motor gear plate member, which is one of the plate members, is arranged so as to sandwich the motor gear perforated plate with the paper winding motor gear.

  According to this configuration, it is particularly easy to reduce the driving sound of the paper winding motor gear.

  Furthermore, in the present invention, a paper winding roller is disposed inside the printing machine and on the paper feed tray, and the perforated plate 1 is disposed above the paper feed tray so as to face the paper winding roller. Preferably, a paper winding roller side perforated plate is disposed, and a paper winding roller side plate member that is one of the plate members is disposed above the paper winding roller side perforated plate.

  According to this configuration, it is particularly easy to reduce the rubbing sound of the paper in the paper winding roller portion located on the paper feed tray.

  Further, in the present invention, the perforated plate has a plurality of perforated plate portions having different aperture ratios, and a partition wall is provided between the perforated plate and the plate member from a boundary portion where the aperture ratio of the perforated plate is different. It is preferable to provide it.

  According to this configuration, it is possible to widen a frequency range having a noise reduction effect. Further, when the porous plate portions and the partition walls are arranged at intervals shorter than the wavelength of the incident sound (the aperture ratio is changed at intervals shorter than the wavelength of the incident sound), the sound absorption efficiency can be further improved.

  Further, in the present invention, a plate heater is disposed between the paper feed tray and the tray lower surface side perforated plate, and a plurality of slits are formed in the plate heater, and the plate heater is arranged from above the plate heater. When the tray lower surface side porous plate is viewed, it is preferable that the through holes formed in the tray lower surface side porous plate can be seen from the slit.

  According to this configuration, even when a plate heater is provided inside the printing press, it is possible to prevent the noise of the printing press from leaking outside while avoiding a significant design change of the printing press.

  Further, in the present invention, the paper feed tray is a tray arranged in the second or higher level from the bottom, and the tray lower surface side porous plate is disposed above and below the tray lower surface side plate member, respectively. A tray lower surface side porous plate and a second tray lower surface side porous plate, wherein the tray lower surface side plate member moves in the vertical direction between the first tray lower surface side porous plate and the second tray lower surface side porous plate. Is preferred.

  According to this configuration, by moving the tray lower surface side plate member in the vertical direction according to the paper feed tray to be used, it is possible to reduce paper collision noise and rubbing sound generated from the paper feed tray being used. That is, a noise reduction structure common to the upper and lower paper feed trays is provided, and space can be saved.

  Furthermore, in the present invention, a paper transport path perforated plate, which is one of the perforated plates, is disposed in a paper transport path inside the printing press so as to face the paper feed tray, and the plate is disposed outside the paper transport path perforated plate. It is preferable that a paper conveyance path plate member which is one of the members is disposed.

  According to this configuration, it is particularly easy to reduce paper collision noise and rubbing noise from the paper conveyance path.

  Further, in the present invention, the paper feed tray is a double wall, and one of the inner wall and the outer wall constituting the side wall of the paper feed tray is a tray side perforated plate which is one of the perforated plates. It is preferable that the other is a tray side plate member which is one of the plate members.

  According to this configuration, if the inner wall is a perforated plate, it is particularly easy to reduce noise generated inside the paper feed tray, such as paper rubbing noise when winding paper. If the outer side wall is a perforated plate, it is particularly easy to reduce the collision noise and rubbing sound of the paper from the outside of the tray side wall, for example, from the paper conveyance path.

  Further, in the present invention, the paper feed tray is a double wall, and one of the perforated plates is a bottom bottom porous plate, one of the lower side wall and the upper side wall constituting the bottom wall of the paper feed tray; It is preferable that the other is a tray bottom plate member which is one of the plate members.

  According to this configuration, it is particularly easy to reduce noise generated inside the paper feed tray, such as paper rubbing sound when winding paper.

  Furthermore, in the present invention, a box-shaped control box is disposed inside the printing press, and among the plurality of plates constituting the control box, a control box perforated plate in which some of the plates are one of the perforated plates; The plate facing the control box perforated plate is preferably a control box plate member that is one of the plate members.

  According to this configuration, while avoiding a drastic design change of the printing press, without adding a new porous plate, a part of the plurality of original plates is made a porous plate, and the other part is a plate without holes. By doing so, the control box itself can be provided with a noise reduction function. Here, an electrical component such as a cigarette motor gear serving as a sound source and a control box that accommodates a base for controlling them are connected by wiring. In order to simplify the wiring inside the printing press, the electrical components and the control box are often placed close together. In addition, the control box normally receives air from the fan for cooling, and a ventilation path is provided around the control box. That is, according to this configuration, noise reduction measures can be taken near the sound source or around the ventilation path where sound leakage is likely to occur, and sound leakage to the outside of the printing press can be easily suppressed.

  Further, in the present invention, a number of through holes are provided in a portion of the frame constituting the printing machine, such as a frame to which the exterior panel is fixed, located in the periphery of the paper feed tray, ventilation path, or paper conveyance path inside the printing machine. Therefore, it is preferable that the frame itself is the perforated plate. In this case, for example, the exterior panel of the printing press serves as a plate member that blocks the passage of air. A number of through holes may be provided in a part of the cover plate of the motor gear inside the printing press, and the cover plate itself may be the perforated plate for reducing noise.

  According to this configuration, it is possible to reduce the noise of the printing press by using an original frame or the like without newly adding a perforated plate.

  In the present invention, it is preferable that the perforated plate has a step portion formed so as to surround the numerous through holes.

  According to this configuration, the rigidity of the porous plate is improved by the step portion. The sound absorption effect due to the porosity is obtained as a result of the vibration energy of the air being converted into heat by the friction around the hole when the air inside the hole vibrates due to the sound pressure, and is dissipated to the surroundings. The larger it is, the more energy is converted into heat by friction, and the sound absorbing effect is increased. However, when the rigidity of the plate member that opens the hole is low, the plate easily vibrates due to the sound pressure, so that the air amplitude relative to the plate becomes relatively small and the sound absorbing effect is lowered. If the rigidity of the perforated plate is increased by providing such a stepped portion, the sound absorption performance by a large number of through holes can be improved. From another viewpoint, as a result of the rigidity of the perforated plate being improved by the stepped portion, a large number of through-holes can be easily formed in a structural member such as a frame constituting the printing press. That is, the number of target parts / members that can be provided with a large number of through holes increases, and sound leakage to the outside of the printing press can be further suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the noise reduction structure inside a printing press in which dust does not generate | occur | produce like the sound absorption member using urethane or glass wool can be provided.

It is the schematic of a printer provided with the noise reduction structure which concerns on 1st Embodiment. It is a perspective view of the sound insulation and sound absorber 51b shown in FIG. It is the schematic of a printer provided with the noise reduction structure which concerns on 2nd Embodiment. It is the schematic of a printer provided with the noise reduction structure which concerns on 3rd Embodiment. It is the schematic of the printer for showing the modification of the noise reduction structure shown in FIG. It is the schematic of a printer provided with the noise reduction structure which concerns on 4th Embodiment. It is the schematic of the printer for showing the modification of the noise reduction structure shown in FIG. It is the schematic of a printer provided with the noise reduction structure which concerns on 5th Embodiment. It is the schematic of a printer provided with the noise reduction structure which concerns on 6th Embodiment. It is the schematic of a printer provided with the noise reduction structure which concerns on 7th Embodiment. It is the schematic of a printer provided with the noise reduction structure which concerns on 8th Embodiment. It is a perspective view of the sound insulation and sound absorbing body shown in FIG. It is the schematic of a printer provided with the noise reduction structure which concerns on 9th Embodiment. It is a graph for demonstrating the performance verification result of the noise reduction structure shown in FIG. It is a graph for demonstrating the performance verification result of what has the noise reduction structure shown in FIG. 4 and the noise reduction structure shown in FIG. It is a graph for demonstrating the performance verification result of what has the noise reduction structure shown in FIG. 4 and the noise reduction structure shown in FIG. It is the schematic of a printer provided with the noise reduction structure which concerns on 10th Embodiment. It is a figure which shows the analysis model for confirming the sound absorption performance of the noise reduction structure shown in FIG. It is a graph which shows the sound-absorption performance analysis result of the noise reduction structure shown in FIG. It is a figure which shows the other form of a perforated plate. It is the schematic of the printer for showing the modification of the noise reduction structure shown in FIG.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In the following embodiment, an example in which the noise reduction structure according to the present invention is applied to a printer is shown. However, in the noise reduction structure according to the present invention, an object to be printed having a paper feed tray is a paper. It can be applied to all types of printing machines (printers, copiers, facsimiles, etc.).
(First embodiment)

(Printer configuration)
FIG. 1 is a schematic diagram of a printer 1 including a noise reduction structure according to the first embodiment. 1A is a cross-sectional plan view of the printer 1, and FIG. 1B is a cross-sectional view taken along line AA of FIG. 1A. Note that only the periphery of the paper feed tray 2 at the bottom of the printer 1 is shown, and the other parts of the printer 1 are not shown (the same applies to other drawings).

  As shown in FIG. 1, the printer 1 includes a paper feed tray 2 for loading paper, a paper winding motor gear M (hereinafter referred to as “motor gear M”), a paper feed tray 2 and a motor gear M housing 70. And a caster 14 attached to the bottom surface of the housing 70.

  The housing 70 includes double-structured bottom plates 5 and 15 having a space inside, and side plates 4 and a back plate 7 fixed to three sides of the bottom plates 5 and 15, respectively. As shown in FIG. 1A, the motor gear M is disposed on the back side of the paper feed tray 2 in the housing 70. The motor gear M is attached to the back plate 7. The motor gear M is for driving a roller for winding paper. The motor gear M may be attached to the side of the paper feed tray 2 (above or below the paper feed tray 2 on the paper surface of FIG. 1A), that is, the side plate 4 or the like.

(Noise reduction structure)
Here, around the paper feed tray 2, roughly divided, three sound insulating and sound absorbing bodies 51 to 53 are arranged as members constituting the printer 1. The sound insulation and sound absorbers 51 to 53 are made of a metal plate such as steel or aluminum (the same applies to sound insulation and sound absorbers according to other embodiments and modifications described later).

(Sound insulation and sound absorber 51)
A sound insulation and sound absorber 51 is disposed below the paper feed tray 2. The sound insulating and sound absorbing body 51 includes a sound insulating and sound absorbing body 51a, and a sound insulating and sound absorbing body disposed adjacent to the sound insulating and sound absorbing body 51a on the front side (the gripping portion side of the paper feed tray 2). 51b. Note that the sound insulating and sound absorbing body 51a and the sound insulating and sound absorbing body 51b may be integrally formed.

  The sound insulation and sound absorber 51a is spaced from the bottom plate 5 (perforated plate) provided with a large number of holes 22 (through holes) facing the paper feed tray 2 and a predetermined distance between the bottom plate 5 and the bottom plate 5 below. And a bottom plate 15 which is arranged open. The bottom plate 15 is not provided with a hole 22. That is, the bottom plate 15 is a plate member that blocks the passage of air. A side opening between the bottom plate 5 and the bottom plate 15 is closed by a part of the side plate 4, a part of the back plate 7, and a part of the skirt side plate 16. The side plate 4, the back plate 7, and the skirt side plate 16 are also not provided with holes 22.

  Here, the bottom plate 5 and the bottom plate 15 correspond to a tray lower surface side porous plate and a tray lower surface side plate member of the present invention, respectively. A part of the side plate 4, a part of the back plate 7, and a part of the skirt side plate 16 correspond to side wall members.

  In this embodiment, since the bottom plate of the casing 70 constituting the printer 1 has a double structure, a hole is made in the bottom plate on the paper feed tray 2 side (inside the casing) to form the bottom plate 5 (porous plate). Thus, a part of the noise reduction structure can be configured, and a drastic design change of the printer 1 due to the addition of the noise reduction structure can be avoided. Further, the bottom plate 15, the side plate 4, and the back plate 7 of the housing 70 can also constitute a part of the noise reduction structure by adjusting the thickness or the like (the noise reduction structure is configured using the housing 70). Similarly, a significant design change of the printer 1 can be avoided. When the bottom plate of the printer has a single structure (single-sheet structure), a porous plate (bottom plate 5) may be provided on the inside of the housing.

  Next, the sound insulating and sound absorbing body 51b is provided between the skirt top plate 3 (perforated plate) facing the paper feed tray 2 and provided with a large number of holes 22, and the skirt top plate 3 below the skirt top plate 3. And a skirt bottom plate 17 disposed at a predetermined interval. The skirt bottom plate 17 is a plate member that blocks the passage of air without the holes 22. A side opening between the skirt top plate 3 and the skirt bottom plate 17 is closed by a part of the side plate 4 and the skirt side plates 16 and 18. The skirt side plate 18 is also not provided with a hole 22.

  Here, the skirt top plate 3 and the skirt bottom plate 17 correspond to the tray lower surface side porous plate and the tray lower surface side plate member of the present invention, respectively. Further, a part of the side plate 4 and the skirt side plates 16 and 18 correspond to side wall members.

  Next, the structure of the sound insulation and sound absorber 51b will be described in detail with reference to FIG. 2 as a representative of the sound insulation and sound absorber according to the noise reduction structure of the present invention. As shown in FIG. 2, the skirt top plate 3 of the sound insulating and sound absorbing body 51b includes a plurality of perforated plate portions 3a and 3b having different aperture ratios. The holes 22 provided in the skirt top plate 3 (perforated plate portions 3a and 3b) are circular. The aperture ratio of the porous plate portion 3a (or 3b) is a plurality of holes provided in the porous plate portion 3a (or 3b) with respect to the surface area of the porous plate portion 3a (or 3b) when the holes 22 are not provided. It means the ratio of the total area of 22. The diameter of the hole 22 is, for example, 0.5 mm. The aperture ratio is, for example, about 0.1% to 1%.

  In addition, the hole provided in the skirt top plate 3 does not need to be circular, and may be elliptical, polygonal, slit-shaped (thin gap), or the like. That is, in the present invention, the term “hole (through hole)” includes a shape such as a circle, an ellipse, a polygon, and a slit (thin gap). Furthermore, the term “perforated plate” in the present invention includes not only those having circular holes, but also those having holes such as elliptical, polygonal, slit-shaped (thin gaps).

  The aperture ratio of the porous plate portion 3a is smaller than the aperture ratio of the porous plate portion 3b. In the present embodiment, perforated plate portions having different aperture ratios are alternately provided. A partition wall 19 is provided at the boundary between the perforated plate portion 3 a and the perforated plate portion 3 b, and the air layer behind the skirt top plate 3 (perforated plate) (rear side with respect to the paper feed tray 2) is divided by the partition wall 19. ing.

  The sound insulation and sound absorber 51a also has a plurality of perforated plate portions having different aperture ratios, and is located between the perforated plate and the plate member from a boundary portion where the aperture ratios of the perforated plates are different. It is preferable to provide a partition wall 19 (internal partition) (the same applies to all sound insulation and sound absorbers described later).

  Here, the principle of noise reduction will be described. When a sound wave such as a paper rubbing sound generated in the paper feed tray 2 enters the hole 22 of the perforated plate portion 3a (or 3b), the sound wave energy is lost due to friction with the inner wall surface of the hole 22. Further, when the sound wave enters the hole 22 of the perforated plate portion 3a (or 3b), a vortex is generated behind the hole 22. This vortex generation causes loss of sonic energy. That is, noise is reduced due to energy loss due to “friction” and “vortex” (sound absorption). Note that sound insulation by the skirt bottom plate 17 that blocks the passage of air also contributes to noise reduction.

  From these, according to the present invention, the porous plate (for example, the skirt top plate 3 and the bottom plate 5) disposed around the paper feed tray 2 inside the housing 70 and the air layer behind it propagate in the air. Noise of the printer 1 (paper collision / rubbing noise, motor gear M drive sound, etc.) can be reduced (paper collision noise / rubbing noise, motor gear M drive noise, etc.). To prevent leakage). Further, since a perforated plate made of a metal material such as steel or aluminum is used, dust is not generated unlike a sound absorbing member made of urethane or glass wool. That is, it is possible to provide a noise reduction structure inside the printer 1 that does not generate dust like the sound absorbing member.

  As to which frequency band sound is absorbed, the diameter of the hole 22, the aperture ratio of the porous plate portion 3a (or 3b), the plate thickness of the porous plate portion 3a (or 3b), the porous plate portion 3a (or 3b) The thickness of the air layer behind is designed as a parameter. As in the present embodiment, by using the skirt top plate 3 (perforated plate) composed of a plurality of perforated plate portions 3a and 3b having different aperture ratios, the frequency range having a noise reduction effect can be widened. it can. In this embodiment, a plurality of perforated plate portions having different aperture ratios are used, but a plurality of perforated plate portions having different diameters of the holes 22 and the thickness of the air layer behind the perforated plate portions may be used. The frequency range having a noise reduction effect can be widened.

  If the porous plate portions 3a and 3b and the partition walls 19 are arranged at intervals shorter than the wavelength of the incident sound (the aperture ratio is changed at intervals shorter than the wavelength of the incident sound), the sound absorption efficiency can be further improved.

  The principle of noise reduction described above is completely different from the sound absorption principle of a so-called Helmholtz resonator. The difference in structure between the sound insulation and sound absorber according to the present invention and the Helmholtz resonator is that the noise reduction structure using the sound insulation and sound absorber according to the present invention has a smaller aperture ratio than the Helmholtz resonator. And the diameter of the hole is small.

(Sound insulation and sound absorber 52)
Returning to FIG. 1, a sound insulating and sound absorbing body 52 is disposed above the paper feed tray 2. The sound insulation and sound absorber 52 is disposed between the tray upper surface side porous plate 11 facing the paper feed tray 2 and provided with a large number of holes 22, and the tray upper surface side porous plate 11 above the tray upper surface side porous plate 11. And a tray upper surface side plate member 12 arranged at a predetermined interval. In addition, the tray upper surface side plate member 12 is a plate member that blocks passage of air in which the hole 22 is not provided. A side opening between the tray upper surface side porous plate 11 and the tray upper surface side plate member 12 is closed by a part of the side plate 4, a part of the back plate 7, and the end face plate 10. The end face plate 10 is also not provided with a hole 22.

  Here, a part of the side plate 4, a part of the back plate 7, and the end face plate 10 correspond to side wall members.

(Sound insulation and sound absorber 53)
A sound insulation and sound absorbing body 53 is disposed on the back side of the paper feed tray 2. The sound insulation and sound absorber 53 includes a first motor gear side porous plate 8, a first motor gear side plate member 6, and a second motor gear side porous plate 9. The first motor gear side porous plate 8 is a porous plate facing the motor gear M and provided with a large number of holes 22. The first motor gear side plate member 6 is a plate member disposed with a predetermined gap between the first motor gear side porous plate 8 and the motor gear M so as to sandwich the first motor gear side porous plate 8. . The second motor gear side perforated plate 9 is a perforated plate facing the paper feed tray 2 and provided with a large number of holes 22. The second motor gear side porous plate 9 and the first motor gear side porous plate 8 are connected at ends. The first motor gear side plate member 6 is a plate member that blocks the passage of air without the holes 22. Further, in the sound insulating and sound absorbing body 53, a part of the back plate 7 corresponds to the second motor gear side plate member according to the present invention which is arranged so as to sandwich the second motor gear side porous plate 9 with the paper feed tray 2. To do.

  In addition, the opening on the two surfaces excluding the first motor gear side porous plate 8, the first motor gear side plate member 6, the second motor gear side porous plate 9, and a part of the back plate 7 (corresponding to the second motor gear side plate member) The bottom plate 5 is closed by a part (the portion without the hole 22) and the top plate 13. Here, a part of the bottom plate 5 (portion without the hole 22) and the top plate 13 correspond to side wall members.

The sound insulation and sound absorbers 51, 52, and 53 have been described above. The sound insulation and sound absorbers 51 and 52 respectively disposed below and above the paper feed tray 2 can greatly reduce paper collision noise and rubbing noise when being fed from the paper feed tray 2. Further, the sound insulation and sound absorber 53 disposed on the back side of the paper feed tray 2 can reduce both the sound of the paper from the paper feed tray 2 and the driving sound of the motor gear M. Furthermore, the driving sound of the motor gear M in the low frequency region (for example, 400 Hz region) can be reduced by using a long space beside the motor gear M to increase the back air layer.
(Second Embodiment)

  FIG. 3 is a schematic diagram of the printer 102 including the noise reduction structure according to the second embodiment. 3A is a plan sectional view of the printer 102, and FIGS. 3B and 3C are an AA sectional view and a BB sectional view of FIG. 3A, respectively. . The description of the same members as those of the printer 1 according to the first embodiment shown in FIG. 1 will be omitted (the same applies to the embodiments and modifications shown below).

  As shown in FIG. 3, in the present embodiment, a sound insulating and sound absorbing body 54 is disposed so as to surround the motor gear M. The sound insulating and sound absorbing body 54 is disposed between the motor gear perforated plate 23 and the motor gear perforated plate 23 so as to sandwich the motor gear perforated plate 23 between the motor gear M and the motor gear perforated plate 23. And a motor gear plate member 24 disposed at a predetermined interval therebetween. The motor gear plate member 24 is a plate member that blocks passage of air without the holes 22. The side opening between the motor gear perforated plate 23 and the motor gear plate member 24 is closed by a part of the back plate 7 and the end plates 26 and 45. The end plates 26 and 45 are also not provided with holes 22.

Here, a part of the back plate 7 described above and the end plates 26 and 45 correspond to side wall members. According to the sound insulation and sound absorber 54 of the present embodiment, it is easy to reduce the driving sound of the motor gear M.
(Third embodiment)

  FIG. 4 is a schematic diagram of a printer 103 including a noise reduction structure according to the third embodiment. 4A is a cross-sectional plan view of the printer 103, and FIG. 4B is a cross-sectional view taken along line AA in FIG. 4A.

  As shown in FIG. 4, in this embodiment, the sound insulating and sound absorbing body 55 is disposed only below the paper conveyance path located on the side of the paper feed tray 2. Reference numerals 21a, 21b, and 21c in FIG. 4 denote paper winding rollers. The sound insulating and sound absorbing body 55 has a paper transport path side porous plate 28 disposed below the paper transport path. A part of the bottom plate 27 located below the paper conveyance path side porous plate 28 corresponds to the paper conveyance path side plate member according to the present invention. Further, the side opening between the paper transport path side perforated plate 28 and the bottom plate 27 is closed by a part of the side plate 4, a part of the back plate 7, and end face plates 29, 31, and 32. The bottom plate 27 and the end plates 29, 31, 32 are not provided with holes 22.

  Here, a part of the side plate 4, a part of the back plate 7, and the end face plates 29, 31, and 32 correspond to side wall members. According to the sound insulation and sound absorber 55 of the present embodiment, it is easy to reduce the collision noise and rubbing sound of the paper from the paper conveyance path.

  In the present embodiment, similarly to the skirt top plate 3 shown in FIG. 2, the perforated plate portions 28a and 28b having different aperture ratios are alternately provided. A partition wall (internal partition) is provided at a boundary portion between the porous plate portion 28a and the porous plate portion 28b, and an air layer below (behind) the paper transport path side porous plate 28 (porous plate) is divided by the partition wall. Yes.

The paper transport path (paper winding roller 21b) may be disposed on the back side of the paper feed tray 2. In this case, the sound insulation and sound absorber 55 is also arranged on the back side of the paper feed tray 2 in accordance with the position of the paper transport path.
(Modification)

  FIG. 5 is a schematic view of printers (104a, 104b, 104c) for showing a modification of the noise reduction structure shown in FIG. 5A, 5B, and 5C are all front sectional views of the printer (cross-sectional views corresponding to FIG. 4B).

  As shown in FIG. 5, sound insulation and sound absorbers (56a, 56b, 56c) disposed below the paper conveyance path may be integrated with the bottom plates 15, 27 of the printer. Thereby, since the air layer behind the perforated plate (paper transport path side perforated plate 28) can be designed to be thick, for example, it is easy to increase the sound absorption effect of sound in the frequency range of 800 Hz to 2000 Hz, and the noise reduction frequency It is also easy to lower the lower limit of the region to 800 Hz or less.

  Further, as shown in FIG. 5 (a), a partition (shown as a side wall member, a lower portion of the end face plate 31) is provided between the bottom plate 15 and the bottom plate 27, and below the rear air layer in the sound insulating and sound absorbing body 56a. By making the width W2 on the side larger than the width W1 on the upper side, the air layer behind the paper transport path side porous plate 28 can be made thicker.

  Further, as shown in FIG. 5B, the sound absorbing effect can be obtained even if the paper transport path side porous plate 28 and the bottom plate 27 are flush with each other.

Furthermore, as shown in FIG. 5C, paper transport path side perforated plates 28a and 28b having a double wall structure may be used. In addition, although illustration is abbreviate | omitted, it is good also as a porous board (paper conveyance path | route side porous board 28) of the wall structure more than triple.
(Fourth embodiment)

  FIG. 6 is a schematic diagram of a printer 105 including a noise reduction structure according to the fourth embodiment. FIG. 6A is a front sectional view of the printer 105, and FIG. 6B is a perspective view showing details of the plate heater.

  As shown in FIG. 6, the printer 105 of this embodiment includes a plate for preventing condensation inside the printer 105 between the lowermost sheet feed tray 2a and the bottom plate 5 (tray lower surface side porous plate). A heater 33 is arranged. The plate heater 33 is made of a metal material such as an aluminum material or a copper material. A heating wire 33 a is attached to the plate heater 33.

  Here, in the present embodiment, the holes 22 formed in the bottom plate 5 can be seen so as to avoid the heating wire 33a and when the bottom plate 5 (tray lower surface side porous plate) is viewed from above the plate heater 33. The plate heater 33 is provided with a plurality of slits 33b. The slit 33b may have a circular shape.

According to the present embodiment, the rubbing sound of the paper from the paper feed tray 2 passes through the slit 33b and enters the hole 22 formed in the bottom plate 5 (tray lower surface side porous plate). That is, even when the plate heater 33 is provided inside the printer 105, noise can be reduced while avoiding a significant design change of the printer 105 (the noise of the printer 105 leaks outside). Can be prevented).
(Modification)

  FIG. 7 is a schematic front cross-sectional view of a printer 105a for illustrating a modification of the noise reduction structure shown in FIG.

As shown in FIG. 7, the bottom plate 35 of the printer 105a may have a single structure (single sheet structure). In such a case, a large number of holes 22 may be provided in the plate heater 34 so as to avoid heating wires (not shown), and the plate heater 34 itself may be a perforated plate. A side opening between the plate heater 34 provided with a large number of holes 22 and the bottom plate 35 is closed by a plate 36. The plate heater 34, the bottom plate 35, and the plate 36 constitute a sound insulating and sound absorbing body 57.
(Fifth embodiment)

  FIG. 8 is a schematic sectional side view of a printer 106 having a noise reduction structure according to the fifth embodiment.

  As shown in FIG. 8, a large opening may be formed in the bottom plate 27 for preventing condensation inside the printer 106. In this case, the sound insulation / sound absorber 58 is disposed above the second-stage paper feed tray 2b from the bottom, and the sound insulation / sound absorber 58 can reduce noise leaking from the opening for preventing condensation.

The sound insulating and sound absorbing body 58 includes a tray upper surface side porous plate 11 and a tray upper surface side plate member 12 arranged so as to sandwich the tray upper surface side porous plate 11 between the paper feed tray 2b. The side openings between the tray upper surface side porous plate 11 and the tray upper surface side plate member 12 are closed on all four sides by the side plate 4, the back plate 7 (not shown), and the like.
(Sixth embodiment)

  FIG. 9 is a schematic front sectional view of a printer 107 having a noise reduction structure according to the sixth embodiment.

  As shown in FIG. 9, the sound insulation and sound absorber 59 is a sound insulation and sound absorber disposed between the paper feed tray 2a and the paper feed tray 2b. The sound insulating and sound absorbing body 59 includes a tray lower surface side plate member 40 that blocks air passage disposed below the paper feed tray 2b, and a first tray lower surface side porous plate 38 disposed above the tray lower surface side plate member 40. And a second tray lower surface side perforated plate 41 disposed below the tray lower surface side plate member 40. The side openings between the first tray lower surface side porous plate 38 and the tray lower surface side plate member 40 and between the second tray lower surface side porous plate 41 and the tray lower surface side plate member 40 are four surfaces such as the side plate 4. Both are closed.

  Further, the sound insulating and sound absorbing body 59 is configured such that the tray lower surface side plate member 40 moves in the vertical direction between the first tray lower surface side porous plate 38 and the second tray lower surface side porous plate 41.

According to this embodiment, the tray lower surface side plate member 40 is moved in the vertical direction in accordance with the paper feed tray 2a (or paper feed tray 2b) to be used, so that the paper feed tray 2a (or paper feed tray 2b) being used is moved. ) Can be reduced. That is, a noise reduction structure common to the upper and lower sheet feed trays 2a and 2b is provided, and space can be saved. In other words, a sufficient sound absorbing effect can be obtained even if the sound insulating and sound absorbing body 59 is thinned.
(Seventh embodiment)

  FIG. 10 is a schematic side sectional view of a printer 108 having a noise reduction structure according to the seventh embodiment.

  As shown in FIG. 10, a perforated plate with the holes 22 facing downward (winding roller side perforated plate 42) may be disposed above the paper winding roller 21a positioned on the paper feed tray 2a. Here, the sound insulating and sound absorbing body 60 disposed above the paper winding roller 21a is disposed above the winding roller side porous plate 42 facing the paper winding roller 21a, and above the winding roller side porous plate 42. And a winding roller side plate member 43 arranged. The side openings between the hoisting roller side porous plate 42 and the hoisting roller side plate member 43 are closed on all four sides by end face plates 44 and the like.

According to the present embodiment, it is particularly easy to reduce the rubbing sound of the paper in the paper winding roller portion located on the paper feed tray 2a.
(Eighth embodiment)

  FIG. 11 is a schematic diagram of a printer 109 having a noise reduction structure according to the eighth embodiment. 11A is a cross-sectional plan view of the printer 109, and FIG. 11B is a cross-sectional view taken along line AA of FIG. 11A. FIG. 12A is a perspective view of the sound insulating and sound absorbing body 61 shown in FIG.

  As shown in FIGS. 11 and 12A, a plurality of rib-shaped protrusions 45 are provided in the paper conveyance path. The protrusion 45 is provided on the side plate 4. The protrusion 45 is for reducing the frictional resistance when the paper passes through the paper conveyance path. When the paper passes through the paper conveyance path, the contact area between the side plate 4 and the paper is reduced by the protrusion 45, so that the frictional resistance of the paper is reduced. However, when the paper passes through the paper conveyance path, a collision sound / rubbing sound generated by the contact between the tip 45a of the protrusion 45 and the paper is propagated.

  Here, in the present embodiment, the perforated plates 46 are respectively disposed between the plurality of protrusions 45. The porous plate 46 is arranged in parallel to the side plate 4. Further, the porous plate 46 is disposed between the tip 45a of the projection 45 and the side plate 4 so that the tip 45a of the projection 45 protrudes in the direction of the paper conveyance path. Openings at the upper and lower ends between the perforated plate 46 and the side plate 4 are closed at both ends by a partition, a bottom plate 27 and the like. The sound insulating and sound absorbing body 61 is constituted by the porous plate 46, the protrusion 45, the side plate 4, the bottom plate 27, and the like.

  The perforated plate 46 corresponds to a paper transport path perforated plate according to the present invention that is disposed in the paper transport path inside the printing press so as to face the paper feed tray 2. The side plate 4 corresponds to a paper conveyance path plate member according to the present invention disposed outside the paper conveyance path perforated plate.

  According to the present embodiment, it is possible to reduce the propagation of the collision sound / rubbing sound generated by the contact between the protrusion 45 and the paper by absorbing the sound while keeping the contact area of the paper small by the protrusion 45.

  Next, FIG. 12B is a perspective view showing a modification of the sound insulating and sound absorbing body 61 shown in FIG. As shown in FIG. 12B, the perforated plate 47 may be disposed obliquely rather than parallel to the side plate 4. In this modification, the plurality of perforated plates 47 are arranged in a zigzag manner with respect to the side plate 4 so that the perforated plates 47 are arranged in a mountain shape as a whole. The upper and lower openings between the plurality of perforated plates 47 and the side plates 4 are closed at both ends by partition walls, the bottom plate 27, and the like. The sound insulating and sound absorbing body 62 is constituted by the perforated plate 47, the side plate 4, the bottom plate 27, and the like.

  The perforated plate 47 corresponds to a paper transport path perforated plate according to the present invention that is disposed in the paper transport path inside the printing press so as to face the paper feed tray 2. The side plate 4 corresponds to a paper conveyance path plate member according to the present invention disposed outside the paper conveyance path perforated plate.

  According to the present embodiment, the number of members constituting the sound insulation and sound absorber 62 can be smaller than the number of members constituting the sound insulation and sound absorber 61. Further, the perforated plates 47 arranged in a mountain shape can reduce the propagation of paper collision sound and rubbing sound by absorbing sound while keeping the paper contact area small.

Furthermore, when a design is made in which the noise reduction frequency region is changed by changing the mutual aperture ratio (the diameter of the hole 22) between the adjacent perforated plates 47 by forming a valley, the opening in the space of the valley Since sound is absorbed in the noise reduction frequency range of the two perforated plates 47 having different rates, the sound absorption efficiency is further increased.
(Ninth embodiment)

  FIG. 13 is a schematic side sectional view of a printer 110 including a noise reduction structure according to the ninth embodiment.

  As shown in FIG. 13, the inner wall 2b1 of the side walls of the paper tray 2b having a double wall structure may be a tray side porous plate, and the outer wall 2b2 may be a tray side plate member (a plate member having no holes). preferable. Note that the four side openings between the inner wall 2b1 and the outer wall 2b2 are closed.

  As a result, it is possible to reduce noise generated inside the paper feed tray 2b, such as paper rubbing noise when winding paper. Note that the same applies to the lowermost sheet feed tray 2a as shown in FIG.

  Although not shown, the outer wall 2b2 of the side wall of the paper tray 2b having a double wall structure may be a tray side porous plate, and the inner wall 2b1 may be a tray side plate member (a plate member having no holes). It is preferable (the same applies to the paper feed tray 2a). Thereby, it is possible to reduce the collision noise and rubbing sound of the paper from the outside of the tray side wall, for example, from the paper conveyance path.

  Further, as shown in FIG. 13, the lower wall 2b3 of the bottom wall of the paper tray 2b having a double wall structure is a tray bottom porous plate, and the upper wall 2b4 is a tray bottom plate member (a plate member having no holes). It is also preferable to do. The side openings between the lower side wall 2b3 and the upper side wall 2b4 are closed on all four sides.

  As a result, it is possible to reduce noise generated inside the paper feed tray 2a located below, such as a paper rubbing sound when winding paper. As shown in FIG. 13, if the bottom wall 2a3 of the bottom wall of the double-walled paper feed tray 2a located at the bottom is a perforated plate and the top wall 2a4 is a plate member without holes, It can prevent the rubbing sound from leaking outside.

Although not shown, the upper wall 2b4 of the bottom wall of the paper tray 2b having a double wall structure is a tray bottom porous plate, and the lower wall 2b3 is a tray bottom plate member (a plate member having no holes). Is also preferable (the same applies to the paper feed tray 2a). Here, when the size of the paper is smaller than the size of the paper feed tray 2 (for example, when A4 paper is put in the paper feed tray for A3), the space above the partial bottom wall of the paper feed tray 2 Exists. According to the present embodiment, the sound that has propagated through the space above the bottom wall, such as the rubbing sound of the paper when the paper is rolled up, is used as a sound insulating and insulating material constituted by the tray bottom perforated plate, the tray bottom plate member, etc. It can be reduced by a sound absorber.
(Noise reduction performance verification results)

  FIG. 14 is a graph for explaining the performance verification result of the noise reduction structure shown in FIG. 4 (a sound insulating and sound absorbing body 55 having a perforated plate is disposed only below the paper conveyance path). FIG. 14A is a graph showing the sound absorption rate of the sound insulation and sound absorber 55, and FIG. 14B is a graph showing the noise measurement result.

  As shown in FIG. 14A, the paper transport path side porous plate 28 constituting the sound insulating and sound absorbing body 55 has a 0.3% opening ratio portion (porous plate portion 28b) and a 0.75% opening. The rate part (perforated plate part 28a) was mixed to form a perforated plate in which partition walls 19 were provided inside the sound absorber from the boundary portions having different aperture ratios of the perforated plate. Under this condition, a noise reduction effect is obtained in the frequency range 800 Hz to 2000 Hz as shown in FIG.

  The noise measurement result shown in FIG. 14B is obtained by measuring the sound leaking from the gap between the bottom of the printer 103 and the installation floor. As can be seen from FIG. 14B, noise can be reduced by 1 dB or more in the frequency range of 800 Hz to 2000 Hz.

  When the porous plate portions 3a and 3b and the partition wall 19 are arranged at intervals shorter than the wavelength of the incident sound (the aperture ratio is changed at intervals shorter than the wavelength of the incident sound), the sound absorption efficiency is averaged as shown in FIG. It can be higher than the value. The same applies to sound insulation and sound absorbers 51, 52, and 53, which will be described later.

  Next, FIG. 15 and FIG. 16 are graphs for explaining the performance verification results of the noise reduction structure shown in FIG. 4 and the noise reduction structure shown in FIG. That is, FIG. 15 and FIG. 16 are graphs for explaining the performance verification results of the noise reduction structure including the sound insulating and sound absorbing bodies 51, 52, 53, and 55.

  FIG. 15A is a graph showing the sound absorption rate of the sound insulation and sound absorber 51b and the sound insulation and sound absorber 52, and FIG. 15B is a graph showing the sound absorption rate of the sound insulation and sound absorber 51a. (A) is a graph which shows the sound absorption rate of the sound insulation and sound absorber 53. FIG.

  As shown in FIG. 15A, the skirt top plate 3 (tray lower surface side porous) constituting the sound insulation and sound absorber 51b and the tray upper surface side porous plate 11 constituting the sound insulation and sound absorber 52 are both A porous plate having a partition wall 19 provided inside the sound absorber from a boundary portion having a different opening ratio of the porous plate was prepared by mixing a 0.3% open area portion and a 1% open portion.

  As shown in FIG. 15B, the bottom plate 5 (tray lower surface side porous) constituting the sound insulating and sound absorbing body 51a has a 0.1% opening ratio, a 0.3% opening ratio, % Of the aperture ratio part was mixed to form a porous plate in which the partition wall 19 was provided inside the sound absorber from the boundary portion where the aperture ratio of the porous plate was different.

  As shown in FIG. 16 (a), the second motor gear side plate member 9 constituting the sound insulating and sound absorbing body 53 mixes a 0.3% aperture ratio portion and a 1% aperture ratio portion so that the porous A perforated plate in which partition walls 19 were provided inside the sound absorber from the boundary portions having different aperture ratios of the plate was used. The opening ratio of the first motor gear side porous plate 8 constituting the sound insulating and sound absorbing body 53 was 0.3% over the entire surface.

The noise measurement result shown in FIG. 16B is obtained by measuring the noise of the bottom plate portion of the printer. As can be seen from FIG. 16B, in this embodiment, noise can be reduced by about 4 dB.
(10th Embodiment)

  FIG. 17 is a schematic perspective view of a printer 111 including a noise reduction structure according to the tenth embodiment.

  As shown in FIG. 17, a substrate box 50 is disposed on the back plate 7 side inside the printer 111. The back plate 7 is composed of an upper panel 7a and a lower panel 7b, and the upper panel 7a is provided with a slit 72 (burr). There is a gap S between the upper panel 7a and the lower panel 7b. The board box 50 is a control box in which a board for controlling electric parts such as the motor gear M serving as a sound source is accommodated. A motor gear M is disposed on the front side of the substrate box 50 so as to be adjacent to the substrate box 50. An arrow shown in FIG. 17 is an arrow indicating a sound propagation path, and a sound generated from the motor gear M itself, a sound generated when the motor gear M vibrates the mounting plate 90, and the like follow the path of the arrow. Leak from the gap S.

  A control box may be arranged on the side plate side inside the printer 111. In FIG. 17, nothing is shown in the lower space of the substrate box 50, but various components are accommodated in this space. The gap spaces between these various components (not shown) and the board box 50 are ventilation paths.

  The substrate box 50 is a rectangular parallelepiped, and includes a back plate 50a, a front plate 50c, side plates 50b and 50d, a top plate 50f, and a bottom plate 50e. A vent hole 71 is provided in the back plate 50a. A large number of holes 22 are provided in the bottom plate 50e. The front plate 50c, the side plates 50b and 50d, and the top plate 50f are not provided with holes.

Here, the bottom plate 50e corresponds to the control box perforated plate of the present invention. The top plate 50f that faces the bottom plate 50e and blocks the passage of air corresponds to the control box plate member of the present invention. An air layer exists between the bottom plate 50e and the top plate 50f. As described above, in this embodiment, the base box itself has a noise reduction structure by forming a part of the plurality of plates constituting the existing substrate box 50 without adding a porous plate. Can do.
(Noise reduction performance verification results)

  The result of sound absorption performance analysis of the noise reduction structure shown in FIG. 17 will be described. FIG. 18 is a diagram showing an analysis model, and FIG. 19 is a graph showing an analysis result.

  As shown in FIG. 18, the analysis model assumes that the sound source M (assuming the motor gear M) is located immediately below the front plate 50c. A gap S between the upper panel 7a and the lower panel 7b was taken as a measurement point. The diameter of the hole 22 provided in the bottom plate 50e is set to φ0.8 mm, and the opening ratio of the bottom plate 50e is changed to 0.5%, 1.0%, 2.0%, and 5.0%, and the bottom plate Comparison analysis was performed with the case where no hole was provided in 50e. The distance (the thickness of the back air layer) between the bottom plate 50e and the top plate 50f was 340 mm.

  As shown in the analysis results in FIG. 19, the noise level can be reduced in almost all frequency ranges compared to the case where no hole is provided at all aperture ratios of 0.5% to 5.0%. ing. In particular, the noise level can be significantly reduced in a low frequency range of about 400 Hz or less.

According to the present embodiment, the control box itself can be provided with a noise reduction function while avoiding drastic design changes of the printer. Here, an electrical component such as a motor gear M serving as a sound source and a control box that houses a base for controlling them are connected by wiring. In order to simplify the wiring inside the printer, the electrical components and the control box are often placed close together. In addition, the control box normally receives air from the fan for cooling, and a ventilation path is provided around the control box (in the present embodiment, under the board box 50 or the board box 50). Is behind the ventilation route). That is, according to the present embodiment, noise reduction measures can be taken near the sound source or around the ventilation path where sound leakage is likely to occur, and sound leakage to the outside of the printer can be easily suppressed.
(Other forms of perforated plate)

  FIG. 20 is a diagram showing another form of the perforated plate. In this example, a large number of holes 22 are provided in a frame 80 constituting the printer, and the frame itself is a perforated plate. Further, the frame 80 is provided with a triangular stepped portion 80 a surrounding the many holes 22. The stepped portion 80a is provided in the frame 80 by, for example, pressing. Note that the shape of the stepped portion 80a is not limited to a triangular shape. In the frame 80, a large number of holes 22 are provided with a noise reduction function, and the strength of the frame 80 is ensured by a portion 80b between adjacent stepped portions 80a. Of each part of the frame 80, a large number of holes 22 are provided in portions located around the paper feed tray, ventilation path, and paper transport path inside the printer. Note that a large number of holes 22 may be provided in all peripheral portions of the paper feed tray, the ventilation path, and the paper conveyance path inside the printer, or a large number of holes 22 may be provided only in any of these peripheral portions.

  Although not shown, outside the frame 80 is an exterior panel that constitutes a printer, such as a back plate and a side plate. These exterior panels serve as plate members that block the passage of air, and the space between the numerous holes 22 (frame 80) formed in the recessed portion toward the inside of the printer and the exterior panel is an air layer. Become.

According to this embodiment, the rigidity of the frame 80 (perforated plate) is improved by the stepped portion 80a. As a result, the sound absorption performance by the large number of holes 22 is improved. From another viewpoint, as a result of the rigidity of the frame 80 being improved by the stepped portion 80a, it is easy to provide a large number of holes 22 in a structural member that requires strength and constitutes a printer. That is, the parts and members to which the noise reduction structure of the present invention can be applied increase. By applying the noise reduction structure of the present invention to many parts and members, sound leakage to the outside of the printer can be further suppressed.
(Modification)

  FIG. 21 is a diagram showing an example in which the form in which the triangular step 80 a shown in FIG. 20 is provided is applied to the substrate box 50. In this modification, a total of four triangular step portions 81 are provided on the back plate 50a of the substrate box 50, and a large number of holes 22 are formed in the recessed portions. That is, the back plate 50a of the substrate box 50 is a perforated plate. The four stepped portions 81 have the same shape and dimensions, and the vertices of the four triangular stepped portions 81 are opposed to each other, and a cross-shaped convex portion 82 is formed between the stepped portions 81 adjacent to each other. . By setting it as such a form, the rigidity of the backplate 50a can be improved, As a result, the sound absorption performance by many holes 22 improves. In addition, the form which provides a level | step-difference part as shown in FIG. 20 and FIG. 21 is applicable also to other above-mentioned embodiment.

  The front plate 50c, the side plates 50b and 50d, the top plate 50f, and the bottom plate 50e of the substrate box 50 are not provided with holes. In the present modification, the front plate 50c of the substrate box 50 serves as a plate member that blocks the passage of air, and a large number of holes 22 (back plate 50a) formed in a portion recessed toward the inside of the substrate box 50. The space between the front plate 50c is an air layer.

  The upper panel 7a portion where the slits 72 are not present and the many holes 22 face each other serves as a plate member that blocks the passage of air, and the space between the upper panel 7a portion and the back plate 50a is air. In some cases, the sound absorption effect is exhibited.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims. .

1: Printer 2: Paper feed tray 4: Side plate (side wall member that blocks passage of air)
5: Bottom plate (tray bottom side perforated plate)
7: Back plate 14: Caster 15: Bottom plate (tray lower surface side plate member)
16: Skirt side plate (side wall member that blocks the passage of air)
22: Hole (through hole)
M: Motor gear for paper winding

Claims (16)

It is a noise reduction structure of a printing press where the object to be printed is paper,
A perforated plate having a large number of through holes is arranged around the paper feed tray, ventilation path, or paper transport path inside the printing machine so that sound waves generated inside the printing machine enter from the through holes,
A plate member that blocks the passage of air is arranged to face the perforated plate,
A noise reduction structure for a printing press, wherein an air layer is formed between the perforated plate and the plate member. The noise reduction structure for a printing press according to claim 1,
A tray lower surface side porous plate, which is one of the porous plates, is disposed below the paper feed tray so as to face the paper feed tray,
A noise reduction structure for a printing press, wherein a tray lower surface side plate member, which is one of the plate members, is disposed below the tray lower surface side porous plate. The noise reduction structure for a printing press according to claim 1 or 2,
The paper winding motor gear is arranged inside the printing machine and around the paper feed tray,
A first motor gear side perforated plate, which is one of the perforated plates, is arranged to face the paper winding motor gear;
A first motor gear side plate member, which is one of the plate members, is disposed so as to sandwich the first motor gear side perforated plate with the paper winding motor gear;
A second motor gear side perforated plate, which is one of the perforated plates, is arranged to face the paper feed tray,
A second motor gear side plate member, which is one of the plate members, is disposed so as to sandwich the second motor gear side porous plate with the paper feed tray;
Noise reduction of a printing press, wherein the first motor gear side porous plate or the first motor gear side plate member and the second motor gear side porous plate or the second motor gear side plate member are connected at ends. Construction. In the noise reduction structure of the printing press in any one of Claims 1-3,
A paper transport path side perforated plate which is one of the perforated plates is disposed below the paper transport path inside the printing press,
A noise reduction structure for a printing press, wherein a paper conveyance path side plate member, which is one of the plate members, is disposed below the paper conveyance path side perforated plate. In the noise reduction structure of the printing press according to any one of claims 1 to 4,
A tray upper surface side perforated plate which is one of the perforated plates is disposed above the paper feed tray so as to face the paper feed tray,
A noise reduction structure for a printing press, wherein a tray upper surface side plate member, which is one of the plate members, is disposed above the tray upper surface side porous plate. In the noise reduction structure of the printing press according to any one of claims 1 to 5,
The paper winding motor gear is arranged inside the printing machine and around the paper feed tray,
A perforated plate for motor gear which is one of the perforated plates is arranged so as to surround the motor gear for paper winding,
A noise reduction structure for a printing press, wherein a motor gear plate member, which is one of the plate members, is disposed so as to sandwich the motor gear perforated plate with the paper winding motor gear. In the noise reduction structure of the printing press according to any one of claims 1 to 6,
A roll-up roller is arranged inside the printing machine and on the paper feed tray,
A paper winding roller side perforated plate, which is one of the perforated plates, is disposed above the paper feed tray so as to face the paper winding roller,
A noise reduction structure for a printing press, wherein a paper winding roller side plate member, which is one of the plate members, is disposed above the paper winding roller side perforated plate. In the noise reduction structure of the printing press according to any one of claims 1 to 7,
The perforated plate has a plurality of perforated plate portions having different aperture ratios,
A noise reduction structure for a printing press, characterized in that a partition is provided between the porous plate and the plate member from a boundary portion where the aperture ratio of the porous plate is different. The noise reduction structure for a printing press according to claim 2,
A plate heater is disposed between the paper feed tray and the tray lower surface side perforated plate,
A plurality of slits are formed in the plate heater,
A noise reduction structure for a printing press, wherein a through-hole formed in the tray lower surface side porous plate is seen from the slit when the tray lower surface side porous plate is viewed from above the plate heater. The noise reduction structure for a printing press according to claim 2,
The paper feed tray is a tray arranged at the second or higher level from the bottom,
The tray lower surface side porous plate is a first tray lower surface side porous plate and a second tray lower surface side porous plate respectively disposed above and below the tray lower surface side plate member,
A noise reduction structure for a printing press, wherein the tray lower surface side plate member moves in a vertical direction between the first tray lower surface side porous plate and the second tray lower surface side porous plate. In the noise reduction structure of the printing press according to any one of claims 1 to 10,
A paper transport path perforated plate, which is one of the perforated plates, is disposed in a paper transport path inside the printing press so as to face the paper feed tray,
A noise reduction structure for a printing press, wherein a paper conveyance path plate member, which is one of the plate members, is disposed outside the paper conveyance path perforated plate. In the noise reduction structure of the printing press according to any one of claims 1 to 11,
The paper feed tray is a double wall,
One of the inner side wall and the outer side wall constituting the side wall of the paper feed tray is a tray side surface perforated plate that is one of the perforated plates, and the other is a tray side surface plate member that is one of the plate members. A noise reduction structure for a printing press, characterized in that In the noise reduction structure of the printing press according to any one of claims 1 to 12,
The paper feed tray is a double wall,
One of the lower side wall and the upper side wall constituting the bottom wall of the paper feed tray is a tray bottom plate that is one of the porous plates, and the other is a tray bottom plate member that is one of the plate members. A noise reduction structure for a printing press, characterized by In the noise reduction structure for a printing press according to any one of claims 1 to 13,
A box-shaped control box is placed inside the printing press.
Among the plurality of plates constituting the control box, a part of the plates is a control box perforated plate which is one of the perforated plates, and a plate facing the control box perforated plate is one of the plate members. A noise reduction structure for a printing press, characterized by being a control box plate member. In the noise reduction structure for a printing press according to any one of claims 1 to 14,
Among the frames of the printing press, a plurality of through holes are provided in a portion located around the paper feed tray, ventilation path, or paper transport path inside the printing press, so that the frame itself is the perforated plate. The noise reduction structure of the printing press. In the noise reduction structure for a printing press according to any one of claims 1 to 15,
The noise reduction structure for a printing press, wherein the perforated plate has a step portion formed so as to surround the plurality of through holes.

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