JP2008012771A - Printing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To constitute a printing apparatus which forms prints of a good image quality to a printing medium by maintaining the printing medium at a proper humidity. <P>SOLUTION: A humidifier X is arranged near a case 10. An inlet 10D is formed at a near position of the humidifier X of wall faces of the case 10. A vent port 10E is formed which sends an exhaust gas from a suction fan 25 that sucks a paper P to a printing position in a printing part inside the case 10 to the outside of the case 10 from a back face of the case 10 via a duct 52. The inside of the case 10 is turned to a negative pressure, and the humidification air from the humidifier X is guided from the inlet 10D to the inside of the case 10, thereby humidifying the paper P. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention includes a housing that houses a medium supply mechanism that supplies a print medium to a print unit and an ink jet print head that prints an image by spraying ink onto the print medium supplied to the print unit. More specifically, the present invention relates to a technique for improving print quality by managing humidity.

  As printing apparatuses that improve print quality by controlling humidity, there are apparatuses described in Patent Document 1 and Patent Document 2.

  In Patent Document 1, in a transfer-type printing apparatus using a photosensitive drum (a copying machine in the literature), a device necessary for image formation such as a photosensitive drum, a charging charger, and a cleaning unit, a registration roller, a paper feeding device, and the like. A humidity control unit is provided on the back side of the main body that houses the container. An air outlet and an air inlet are formed in the main body, and both ends of the humidity control unit are connected to the air outlet and the air inlet, and a fan is provided at the connecting portion.

  An air flow path is formed in the upper space of the central part of this humidity control unit, a water storage tank for storing purified water is formed in the lower part, a heater for dehumidification is provided in the air flow path, and a humidifying tank is provided at the bottom of the water storage tank A heater is provided, and a humidity sensor is provided inside the humidity control unit.

  The humidity detected by the humidity sensor is compared with a predetermined optimum humidity in the machine. If the difference from the optimum humidity in the machine is large, the fan speed is increased. The control mode is set so that the humidification heater is turned on when humidifying is performed. By performing this control, the influence from the external environment where the apparatus is installed is minimized, and the occurrence of a partial abnormal image is prevented and good image formation is maintained.

  In Patent Document 2, in a printing apparatus (in the document, a color thermal printer), humidity control paper as a humidity control material is provided inside a magazine that accommodates long thermal paper in a roll shape. The humidity control paper has a function of absorbing moisture when the humidity is high and releasing moisture when the humidity is low, and maintains the humidity in the magazine at the standard humidity. As a result, it is possible to record an image with good density and color balance.

JP-A-9-81018 JP-A-10-29355

  There are two types of print media used in a printing apparatus having an ink jet type print head: a swollen type and a porous type, and a porous type paper is used in order to obtain the same gloss as a print using photosensitive paper. There are many things. Although this paper forms a layer of resin or the like on the surface to create a glossy surface, it has a structure in which many fine holes are formed to absorb ink sprayed from the print head from the surface. Is somewhat hard.

  As described above, since this type of paper has a hard surface, the surface may be finely cracked in a low humidity environment. It is also known that since many fine holes are formed on this surface, the influence of humidity is great, and when the humidity is low, fine cracks are likely to occur on the surface. Such a phenomenon that causes cracking often occurs when the paper surface is bent in a direction in which tension is applied. Therefore, when this type of paper is wound in a roll shape with the surface to which ink is sprayed on the outside, when the paper is bent in a direction in which the bending direction of the roll is further bent, the surface is likely to crack. It becomes. When cracks are generated on the surface in this way, not only the gloss of the surface is impaired, but also the ink that has been sprayed blurs and the image quality is degraded.

  Since roll-shaped printing paper is transported to the print head in a form that is wound around a roller, cracks may occur on the surface during transportation. When printing is performed, it is desired to increase the humidity of the printing paper to an appropriate level.

  However, as described in Patent Document 1, in the case of evaporating water at the time of humidification, since it is necessary to supply water to the inside of the apparatus in the season when the air dries, it takes time and effort. Like a thing described in patent documents 2, it is thought that humidification cannot fully be performed in the season when air dries, and there is room for improvement.

  An object of the present invention is to rationally configure a printing apparatus that maintains a print medium at an appropriate humidity and forms a print with good image quality on the print medium.

A feature of the present invention is that a housing includes a medium supply mechanism that supplies a print medium to a print unit and an ink jet print head that prints an image by spraying ink onto the print medium supplied to the print unit. Printing device
A humidifier for generating humid air is installed outside the housing, and an inlet for guiding the humid air from the humidifier to the inside of the housing is formed in the housing, and the air inside the housing is discharged. Therefore, a negative pressure generating mechanism for generating a negative pressure inside the housing is provided.

  With this configuration, by generating a negative pressure inside the casing by the negative pressure generating mechanism, the humidified air generated by the humidifier can be sucked into the casing together with the outside air from the inlet formed in the casing. As a result, since a configuration having a humidifier outside the conventional printing apparatus is sufficient, the structure of the conventional printing apparatus is not fundamentally changed, and an improvement such as a negative pressure generation mechanism is added. Even when printing is performed in a humidity environment, humidified air generated by a humidifier installed outside the housing is sucked into the housing to maintain the print medium at an appropriate humidity. A printing apparatus that eliminates scratches and prints with good image quality on a print medium has been rationally configured.

  According to the present invention, the printing unit arranges a plate having a plurality of through holes at a printing position where printing is performed by the print head, and sucks air from the through holes of the plate, whereby the print medium is placed on the plate. In addition, the suction fan may be used as the negative pressure generating mechanism by providing an exhaust path for sending air sucked by the suction fan to the outside of the housing.

  With this configuration, a suction fan for adsorbing the print medium to the printing position in the printing unit is used as the negative pressure generation mechanism, so that a special fan is not required as the negative pressure generation mechanism, and the structure is simple. However, the humidity of the print medium can be properly maintained.

  The present invention includes a humidity sensor inside the casing, and when the humidity measured by the humidity sensor falls below a target humidity value, the humidifier is operated and the negative pressure generating mechanism Humidity control means for performing control to generate pressure may be provided.

  With this configuration, when the humidity measured by the humidity sensor falls below the target humidity value, the humidified air generated by the humidifier can be sucked into the housing and printed in a low humidity environment. Even when performing printing, the humidity of the print medium can be maintained appropriately.

  In the present invention, the introduction port may be formed on a side surface of the housing, and an exhaust port for air sent out from the negative pressure generating mechanism may be formed on the back surface of the housing.

  With this configuration, it is reasonable to arrange the humidifier at the side position of the casing. By arranging the humidifier at the side position of the casing in this way, for example, an operator can stand in front of the casing. When the work is performed, the humidifier does not interfere with the work, and a discharge port for sending air from the negative pressure generating mechanism is formed on the back of the housing. The work can be done comfortably without being blown out directly.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
〔overall structure〕
As shown in FIGS. 1 and 2, two magazine accommodating portions A and A are arranged at the lower portion of the housing 10, and an ink jet type printing portion B that performs printing by spraying ink is arranged at the upper portion of the housing 10. A sorting unit 12 that arranges an ink storage unit C on the side of the housing 10 and further feeds a paper P (an example of a print medium) having a relatively small size to the upper surface of the housing 10 by the laterally feeding belt 11; A rack plate 13 for receiving a large size paper P is disposed, and a humidifier X is installed outside the housing 10 to constitute an ink jet printing apparatus.

  In this printing apparatus, as the paper P, a porous ink receiving layer having a large number of fine pores is formed on the surface side of the base on which the resin coat film is formed on the front and back surfaces, so that the surface has a glossy surface. The type is used.

  The two magazine housing portions A and A are arranged in a vertically positioned relationship, and each magazine housing portion A includes a drawer 15 that can be opened and closed by a slide operation integrated with the front wall body 10A. It is configured so that it can be set. The magazine M includes a case 1 in which a space for accommodating a roll-shaped paper P serving as a print medium is formed, a pair of support rollers 2 that support the paper P in the case, and a pressure bonding that conveys the paper P by pressure. A mold feed roller 3 is provided (see FIG. 3).

  The print unit B is configured to print an image on the paper P supplied from the magazine housing unit A by spraying ink with the print head H (see FIGS. 4 and 5). An upper wall 10B formed with a transparent resin plate window W is provided on the front surface of B so as to be freely opened and closed.

  In the ink reservoir C, a plurality of ink cartridges 16 of different hues are exchangeably disposed inside a side wall 10C that can swing and open around an axial center in a vertically oriented posture. Each ink cartridge 16 encloses black (BK), light black (LK), cyan (C), magenta (M), light cyan (LC), light magenta (LM), and yellow (Y) ink. Seven colors are used. Although not shown in the drawing, the ink jet type printing apparatus feeds the ink enclosed in the ink cartridge 16 by air pressure, temporarily stores it in a sub tank (not shown), and then supplies it to the print head H. An ink supply system is provided.

[Conveyance system configuration]
As shown in FIGS. 3 to 5, the printing apparatus supplies the paper P from the magazine M to the printing unit B by a supply unit U1 (an example of a medium supply mechanism), and the printing unit B receives a print transport unit U2. The printing process is executed while transporting the sheet, and after this printing, the cutter unit U3 cuts the print size. Thereafter, the printing unit transfers it from the switchback unit U4 to the discharge unit U5. It has a transport system that sends it to the outside.

  The supply unit U1 includes a guide body 18 provided in the upper magazine housing portion A and a paper P sent out from the upper magazine M so as to guide the paper P sent out from the lower magazine M upward. And a guide body 19 for guiding the upper side of the upper side. As shown in FIG. 3, the supply unit U <b> 1 includes a first motor D <b> 1 that drives the support roller 2 and the feed roller 3 to feed the paper P from the magazine M and rewind the magazine M. I have.

  The print transport unit U2 includes a pressure-bonded first transport roller 21 disposed on the upstream side of the print head H, and a pressure-bonded second transport roller 22 disposed on the downstream side of the print head H. A guide plate 23 is provided for guiding the back side of the paper P at an intermediate position between the first and second transport rollers 21 and 22. Below the guide plate 23, a negative pressure case 24 that applies a negative pressure to the paper P through a large number of through holes 23 A formed in the guide plate 23, and air inside the negative pressure case 24 is discharged. And a suction fan 25 that generates a negative pressure.

  The first conveyance roller 21 includes a driven roller 21A for pressure-conveying the paper P, and the second conveyance roller 22 includes a driven roller 22A for pressure-conveying the paper P. A belt drive interlock 26 that synchronously drives the second transport roller 22 is provided. The print transport unit U2 includes a second motor D2 that drives the first transport roller 21 and the second transport roller 22 in synchronization.

  The print unit B supports a carriage 29 on a slider 28 guided by a guide rail 27 arranged in a posture along the main scanning direction (the width direction of the paper P), and the print head H is disposed on the lower surface side of the carriage 29. Support.

  A timing belt type driving belt 31 is wound around a pair of pulleys 30 arranged in the vicinity of both ends of the guide rail 27, and a scanning motor DS for main scanning that drives one pulley 30 is provided. By fixing the carriage 29, the pulley 30 is driven and rotated by the driving force of the scanning motor DS, and the print head H is reciprocated integrally with the carriage 29.

  With such a configuration, when printing an image on the paper P, the paper P is supplied to the printing position by the first and second transport rollers 21 and 22, and negative pressure is applied from the many through holes 23A of the guide plate 23. As a result, the carriage 29 is operated in one direction along the main scanning direction in a state in which the paper P is attracted to the guide plate 23 and the plane accuracy of the paper P is increased (with the operation in the main scanning direction). In conjunction with this operation, an image is printed with a print width set by spraying ink from the print head H onto the paper P.

  By starting printing in this way, after the carriage 29 reaches the operating end, the first and second transport rollers 21 and 22 transport the paper P by a unit transport amount corresponding to the print width, and thereafter While the carriage 29 is operated in the other direction (reverse direction) along the main scanning direction, a printing operation with a print width is performed in conjunction with this operation. By repeating this printing operation, an image is printed on the paper P.

  The cutter unit U3 includes a fixed blade 35 fixed to a frame (not shown), a movable blade 36 that is operably supported, a cutter motor DC that drives the movable blade 36, and a cutter motor DC. A crank-type drive mechanism 37 that converts a rotational drive force into a reciprocating force, and a pressure-type discharge roller 38 that transports the paper P that has passed through the cutting position of the cutter unit U3. A third motor D3 for driving is provided.

  The switchback unit U4 includes a driving roller 40, a free-rotating reversing roller 41 disposed at a position where it is pressed against the driving roller 40, and the reversing roller 41 operates 90 degrees in both forward and reverse directions around the axis of the driving roller 40. And a reversing mechanism. In the switchback unit U4, the paper P fed from the front end side by being conveyed by the discharge roller 38 is further conveyed in a state where it is pressure-bonded by the driving roller 40 and the reverse roller 41, and as indicated by an arrow in FIG. In addition, after the reversing roller 41 is rotated 90 degrees around the axis of the driving roller 40, the driving roller 40 is reversed to feed the paper P from the rear end side to the discharge unit U 5, and the paper P is turned upside down. It is configured to let you.

  The switchback unit U4 includes a fourth motor D4 that drives the driving roller 40, and a reversing motor DR that reversely operates the reversing roller 41 as the reversing mechanism.

  The discharge unit U5 includes a plurality of pressure rollers 45 for transporting the paper P, and a path for feeding the paper P transported by the pressure rollers 45 to either the lateral feed belt 11 or the rack plate 13 at the top of the housing. A switching mechanism (not shown) is provided, and a fifth motor D5 that drives the pressure roller 45 is provided.

  The humidifier X includes a case 5, a tank 6 for storing water, a transpiration mechanism 7, and a discharge unit 5 </ b> A that sends out the humidified air from the transpiration mechanism 7 together with the air flow created by the discharge fan 8. Yes. The transpiration mechanism 7 has a structure in which water stored in the tank 6 is brought into contact with a heater to send it out as water vapor, and water stored in the tank 6 is sucked up into a mat or the like and vaporized by bringing it in contact with air from a fan or the like. Alternatively, the humidifier X is controlled by a control device 50 provided inside the housing 10. The humidifier X is controlled by a controller 50 provided inside the housing 10. Is done.

[Configuration for humidification]
As shown in FIGS. 1 and 6, the sorting unit 12 of the casing 10 of the printing apparatus is formed in a shape protruding sideways, and the humidifier X is disposed at a lower position. In addition, a plurality of inlets 10D that allow introduction of humidified air from the humidifier X are formed on the side surface of the casing 10 located below the sorting unit 12, and the casing 10 includes a casing. A negative pressure generating mechanism N that makes the inside of the body 10 negative is provided, and a humidity sensor Sh that measures humidity is provided inside the housing 10.

  The introduction port 10 </ b> D is formed in a louver shape in which a plurality of guide plates 51 are arranged in a horizontally long posture, and is configured to guide humidified air from below to the inside of the housing 10 with the plurality of guide plates 51. The suction fan 25 is also used as the negative pressure generation mechanism N, and a duct 52 is provided as an exhaust path for sending air sent from the suction fan 25 from the negative pressure case 24. A discharge port 10 </ b> E for sending out to the outside is formed on the back surface of the housing 10.

  In the present invention, a dedicated fan may be provided as the negative pressure generating mechanism N. In this case, the negative pressure generating mechanism N is configured by attaching a fan to the outer wall surface of the housing 10 without providing ducts.

  The control device 50 pulls out the paper P accommodated in the magazine M by the supply unit U1 and supplies it to the printing unit B, performs the printing process by the conveyance by the print conveyance unit U2, and the paper P printed in this way. Control is performed by cutting with the cutter unit U3 and, after this cutting, sending from the switchback unit U4 to the discharge unit U5 for discharge, and at the same time, maintaining the humidity inside the housing 10. In order to maintain this humidity, the control device 50 is provided with humidity control means HC made of software, and a control system for humidity control will be described below.

[Control system configuration]
As shown in FIG. 7, a signal system for inputting the measurement result from the humidity sensor Sh to the control device 50 is formed, and the humidifier X is connected from the control device 50 via the power control unit PS. An output system for controlling and controlling the suction fan 25 via the power control unit PS is formed.

  In this printing apparatus, the power control unit PS can receive power by inserting plugs of the power cord 9 of the humidifier X so that the commercially available humidifier X can be operated using a commercial power source. It is configured. The power control unit PS assumes a state in which power from a commercial power source is energized and a unit using a relay or a power control element so as to cut off the power. It may be configured to supply electric power to the humidifier X.

  The control mode of the humidity control means HC of the control device 50 can be shown as a flowchart in FIG. That is, the measured value of the humidity sensor Sh is acquired, and when the measured humidity is less than the set value, the humidifier X is activated to drive the suction fan 25 (Steps # 101 to # 103).

  In this humidity control, when the humidity inside the housing 10 is less than the set value, the humidifier X is operated to generate humid air, and at the same time, the suction fan 25 is driven to drive this suction fan. The air sucked in 25 is sent from the duct 52 to the discharge port 10E, and is discharged from the discharge port 10E to the outside of the housing 10. As a result, a negative pressure is generated inside the housing 10. By generating negative pressure in the housing 10 in this way, humidified air generated by the humidifier X is sucked into the housing 10 from the inlet 10D to increase the humidity inside the housing 10. . Further, when the humidity inside the housing 10 exceeds the set value, it is not necessary to operate the humidifier X and the suction fan 25 (when a target area described later is reached) or the humidifier X has already been reached. Therefore, the control for operating the humidifier X and the suction fan 25 is not performed.

  Next, when the humidity measured by the humidity sensor Sh exceeds the set value and reaches the target area, it is determined whether the print process is being performed. X is stopped, and when the printing process is not performed, the humidifier X and the suction fan 25 are stopped, and this process is continued until the control is reset (steps # 104 to # 108).

  In this control, the target area is a humidity area indicating that the humidity inside the housing 10 has reached a value suitable for print processing, and when the target area has been reached (exceeds the target area). In other cases, it is not necessary to perform humidification. Therefore, only the humidifier X is stopped during the printing process, and the humidifier X and the suction fan 25 are stopped when the printing process is completed. It is.

  As described above, according to the present invention, the negative pressure generating mechanism N that makes the inside of the casing 10 of the printing apparatus negative is provided, the introduction port 10D is formed in the casing 10, and the position near the introduction port 10D is formed. By installing the humidifier X, the humidified air from the humidifier X is supplied from the inlet 10D to the inside of the casing 10 without providing a duct or the like for introducing the humidified air generated by the humidifier into the casing 10. Therefore, it is possible to increase the humidity of the paper P and maintain high print quality. As this humidifier X, it is possible to use a commercially available one. When a commercially available one is used, not only the cost can be reduced, but also, for example, the humidifier X is supplied with water. The work can be done easily and the maintenance becomes easy.

  Further, by controlling the negative pressure generating mechanism N and the humidifier X based on the measurement result of the humidity sensor Sh, even when operating in a low humidity environment, the target humidity of the air inside the housing 10 can be adjusted. Making it possible to maintain.

  In particular, as the negative pressure generation mechanism N, the suction fan 25 originally provided in the printing unit B is also used, so that no special fan is required to generate the negative pressure, and the cost is reduced with a simple configuration. Is possible. In the case where the suction fan 25 is also used as the negative pressure generating mechanism N in this way, the inside of the housing 10 is always at a negative pressure when printing is performed. It is possible to increase the humidity of the paper P by introducing humidified air from X into the housing 10.

Perspective view showing the entire photo printing device Perspective view of photo printing device with part open Partial cutaway side view of photo printing device Diagram showing paper transport system The perspective view which shows the conveyance structure of the paper of a printing part Partial cutaway front view of photo printing device Block diagram of control system Flow chart of humidity control

Explanation of symbols

10 Housing 10D Inlet 23 Plate (Guide plate)
25 Suction fan 52 Exhaust path (duct)
A Magazine storage section B Print section H Print head HC Humidity control means P Print medium (paper)
N Negative pressure generation mechanism Sh Humidity sensor U1 Medium supply mechanism (supply unit)
X humidifier

Claims (4)

A printing apparatus in which a housing includes a medium supply mechanism that supplies a print medium to a print unit and an ink jet print head that prints an image by spraying ink onto the print medium supplied to the print unit. And
A humidifier for generating humid air is installed outside the housing, and an inlet for guiding the humid air from the humidifier to the inside of the housing is formed in the housing, and the air inside the housing is discharged. A printing apparatus comprising a negative pressure generating mechanism for generating a negative pressure inside the casing.   The printing unit arranges a plate having a plurality of through holes at a printing position where printing is performed by the print head, and sucks the print medium to the plate by sucking air from the through holes of the plate. The print according to claim 1, wherein the suction fan is used as the negative pressure generating mechanism by being provided with a fan and having an exhaust path for sending air sucked by the suction fan to the outside of the housing. apparatus.   A humidity sensor is provided inside the housing, and when the humidity measured by the humidity sensor falls below a target humidity value, the humidifier is operated and a negative pressure is generated by the negative pressure generating mechanism. The printing apparatus according to claim 1, further comprising a humidity control unit that performs control.   The print according to any one of claims 1 to 3, wherein the introduction port is formed on a side surface of the casing, and a discharge port for air sent out from the negative pressure generating mechanism is formed on the back surface of the casing. apparatus.

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