JP2006030415A - Paper ejection mechanism for printing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper ejection mechanism that sufficiently cools printing paper being conveyed, without sacrificing high printing speed, avoids trouble resulting from complex control, and is widely and effectively used even for regular paper. <P>SOLUTION: The paper ejection mechanism 1 for a printing device M ejects printed paper P onto an external stacker 3 through an ejection port 2. The paper ejection mechanism 1 is composed of a cooling mechanism 6 including: a air nozzle 4 having a air slit 4s which extends in the direction Fb of the printing paper P ejected from the ejection port 2 and through which a current of air is sent to the printing paper P over the area Zb corresponding to the entire width of the printing paper P; and a fan 5 for sending a current of air to the air nozzle 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a paper discharge mechanism of a printing apparatus that discharges printed printing paper onto an external stacker through a discharge port.

  In general, in an image forming apparatus (printing apparatus) using an electrophotographic system, a toner image obtained by a developing unit is transferred to a printing paper to be conveyed, and the toner image transferred to the printing paper is transferred to a fixing unit. The printing paper heated and pressurized by the toner image and having the toner image fixed thereon is discharged to a paper discharge mechanism. Therefore, the high-temperature printing paper heated by the fixing unit is discharged to the paper discharge mechanism. By the way, the time required for the printing paper to reach the paper discharge mechanism from the fixing unit tends to be shortened along with the demand for downsizing the printing apparatus and increasing the printing speed. In this case, high-temperature printing paper that is not sufficiently cooled is stacked on the paper discharge mechanism, and as a result, the toner is peeled off between the printing papers, or the printing papers are stuck via the toner. Problems such as blocking phenomenon occur.

For this reason, conventionally, the type of printing paper is determined by a paper type sensor, and in the case of printing paper that tends to stick, the paper is transported after being temporarily stopped on the transport path and cooled by the atmosphere immediately before paper discharge. Japanese Patent Laid-Open No. 2002-268305 also discloses an image forming apparatus (paper discharge mechanism) that prevents printing paper from sticking after discharge by restarting and discharging.
JP 2002-268305 A

  However, the conventional image forming apparatus (paper discharge mechanism) described above has the following problems.

  First, since the conveyance of the printing paper is temporarily stopped, it is not possible to meet the demand for high-speed printing, and the printing paper is simply stopped, so that the printing paper cannot be sufficiently cooled.

  Secondly, since the temporary conveyance stop control is performed according to the type of printing paper, it is necessary to distinguish the printing paper by a paper type sensor, and the control is complicated, and special paper such as OHP paper is considered. Therefore, it cannot be used universally and effectively for plain paper.

  An object of the present invention is to provide a paper discharge mechanism of a printing apparatus that solves the problems existing in the background art.

  In order to solve the above-described problem, the present invention discharges the printed printing paper P from the discharge port 2 when configuring the discharge mechanism 1 of the printing apparatus M that discharges the printed paper P onto the external stacker 3 through the discharge port 2. A cooling mechanism 6 having a blower nozzle 4 having a blower slit 4s that can blow air over the entire width range Zb of the print paper P along a width direction Fb of the print paper P and a blower fan 5 that blows air to the blower nozzle 4. Is provided.

  In this case, according to a preferred aspect of the invention, the cooling mechanism section 6 has a blower duct 11 that connects the blower fan 5 and the blower nozzle 4 in communication, and the blower duct 11 is used to select an arrangement site of the blower fan 5. Can do. The air blowing slit 4s can set the opening width Lw so that the wind speed in the width direction Fb of the printing paper P is uniform. Furthermore, the forced cooling part 12 which forcibly cools the air blow W from the blower fan 5 can also be provided.

  According to the paper discharge mechanism 1 of the printing apparatus M according to the present invention as described above, the following remarkable effects can be obtained.

  (1) Since the cooling mechanism unit 6 including the air blowing nozzle 4 having the air blowing slit 4s and the air blowing fan 5 that blows air to the air blowing nozzle 4 is provided, the printing paper P to be conveyed can be conveyed without sacrificing the printing speed. Sufficient cooling can be performed.

  (2) Since cooling can be performed without being influenced by the paper type, it is possible to avoid problems that cause complicated printing paper type discrimination and control by the sensor, and it is versatile and effective for plain paper. Available.

  (3) When the cooling mechanism unit 6 is configured according to a preferred aspect, a blower duct 11 that connects the blower fan 5 and the blower nozzle 4 to each other is provided, and an arrangement site of the blower fan 5 is selected by the blower duct 11. In addition, it is possible to avoid the problem of taking in warm air around the fixing unit, and it is possible to effectively use dead space and save space by improving design flexibility.

  (4) If the opening width Lw of the blowing slit 4s is set so that the wind speed in the width direction Fb of the printing paper P becomes uniform according to a preferred aspect, the entire surface of the printing apparatus P conveyed at a constant speed Can be cooled uniformly.

  (5) If the forced cooling part 12 which forcibly cools the air blow W from the blower fan 5 is provided according to a preferred aspect, the cooling effect can be further enhanced.

  Next, the best embodiment according to the present invention will be given and described in detail with reference to the drawings.

  First, in order to facilitate understanding of the present invention, an overview of the entire printing apparatus M will be described with reference to FIGS.

  FIG. 8 shows an external configuration of the printing apparatus M. The printing apparatus M roughly includes a paper feeding unit U1, a transport unit U2, a color printing unit U3, and a paper discharge mechanism 1 according to the present embodiment. Reference numeral 65 denotes an operation unit. This printing apparatus M can be used particularly for business purposes, and a large amount and a wide range of sizes can be used for the printing paper P ... such as business card printing to poster printing.

  FIG. 9 shows a schematic configuration of a mechanical system in the printing apparatus M, and the positional relationship corresponds to the external configuration of the printing apparatus M shown in FIG. The paper feed unit U1 includes a paper feed mechanism 66. The paper feed mechanism 66 has a paper feed tray 67 on which a large amount of printing paper P can be set, and a paper feed elevator mechanism 68 that raises and lowers the paper feed tray 67. And a paper feed roller mechanism 69 that feeds the print paper P one by one from the print paper P on the paper feed tray 67. In this case, the paper feed elevator mechanism 68 includes a face control sensor (not shown) for detecting the top surface position of the printing paper P stacked on the paper feed tray 67. If the top surface position is lowered, the paper feed elevator mechanism 68 is fed. The paper elevator mechanism 68 is driven and controlled, and the top surface position is always maintained at a fixed position.

  The transport unit U2 includes a plurality of transport rollers 72, and has a function of transporting the printing paper P sent out from the paper feed roller mechanism 69 to the color printing unit U3. In this case, the interval between the conveying rollers 72 is set to be shorter than the minimum size of the printing paper P to be conveyed. In addition, the transport unit U2 includes various correction functions such as a skew correction function that uniformly aligns the angle (orientation) of the printing paper P to be transported.

  The color printing unit U3 includes a developing unit 73, a transfer unit 74, and a fixing unit 75 as main components. In this case, the developing unit 73 has a function of forming an electrostatic image on a semiconductor drum (photoconductor) based on print image data transferred from a computer C, which will be described later, and attaching color toner to the electrostatic image. And a Y (yellow) developing unit 73y, an M (magenta) developing unit 73m, a C (cyan) developing unit 73c, and a Bk (black) developing unit 73bk. Further, the transfer unit 74 has a function of transferring the toner image obtained by the developing unit 73 to the conveyed printing paper P. Further, the fixing unit 75 has a function of fixing (fixing) the toner image transferred to the printing paper P by the transfer unit 74 to the printing paper P by heating and pressing. On the other hand, the paper discharge mechanism 1 constitutes a main part of the present invention, and a specific configuration and function will be described later.

  The printing apparatus M is used by connecting to a computer. FIG. 10 shows a printing system S in which a printing apparatus M and a computer C are connected. In this case, the interface 51 of the printing apparatus M and the interface 52 of the computer C are connected by the connecting means 53. The interfaces 51 and 52 may be a parallel method or a serial method. Further, the connection means 53 may be a wired system or a wireless system. The printing apparatus M includes a main part including a print controller 54, a memory 55, and the like. In the printing apparatus M, printing is performed under the control of the print controller 54. On the other hand, the computer C can be a general-purpose personal computer including main parts such as a processing unit 57 including a CPU and the like, and a memory 58 including a hard disk, a ROM, a RAM, and the like. In particular, the computer C includes a printer driver 60 installed by application software, and various printing conditions for operating the printing apparatus M are set by the printer driver 60, and print image data is transferred from the computer C to the printing apparatus M. Forwarded to The computer C and the printing apparatus M can perform two-way communication, and printing under the control of the computer C is also possible.

  Next, a specific configuration and function (action) of the paper discharge mechanism 1 according to the present embodiment will be described with reference to FIGS.

  As shown in FIG. 1, the paper discharge mechanism 1 includes a discharge roller 21 that discharges the printing paper P sent from the fixing unit 75 to the outside. The discharge roller 21 forms a housing 20 that forms the outer surface of the printing apparatus M. It is attached to the discharge port 2 in FIG. The discharge roller 21 includes a pinch roller 21u and a guide roller 21d that are arranged vertically. Further, the paper discharge mechanism 1 includes a stacker mechanism 22 that receives the printing paper P discharged from the discharge roller 21 (discharge port 2). The stacker mechanism 22 includes a stacker support portion 23 and a stacker 3 supported by the stacker support portion 23, and the print sheets P... Discharged from the discharge roller 21 are sequentially stacked on the stacker 3 and stacked. Due to the function of the support portion 23, the stacker 3 descends sequentially according to the weight of the stacked printing sheets P. The fixing unit 75 includes an upper and lower fixing roller 75u and a pressure roller 75d, and a pair of upper and lower guide plates 77u and 77d are disposed between the fixing unit 75 and the discharge roller 21.

  On the other hand, according to the present invention, the paper discharge mechanism 1 includes a cooling mechanism unit 6 that blows air to the printing paper P that is discharged from the discharge roller 21. The paper P is cooled (air cooled). As shown in FIG. 3 (FIG. 2), the cooling mechanism 6 can blow air along the width direction Fb of the print paper P discharged from the discharge port 2 (discharge roller 21) and to the full width range Zb of the print paper P. A blower nozzle 4 having a blower slit 4s, a blower fan 5 for blowing air to the blower nozzle 4, a blower duct 11 for connecting the blower fan 5 and the blower nozzle 4 in communication, and a blower nozzle 4, a blower fan 5 and a blower duct. 11 is configured as an integrated blower unit A. As shown in FIG. 8, the air blowing unit A configured as described above can be attached to the outer surface (rear surface) of the housing 20 located immediately above the discharge port 2.

  The blower nozzle 4 is formed in a rectangular tube shape having a rectangular cross section as a whole, and as shown in FIG. 4, a blower slit 4s is provided on the discharge roller 21 side in the bottom surface portion 4d. In this case, the air blowing slit 4s is formed by extending the lower end of the rear surface portion 4r downward and by bending the rear side of the bottom surface portion 4d downward at a midpoint at a right angle, thereby blowing the air downward. Is provided. As a result, the air blow W blown downward from the air outlet 4oi is blown onto the upper surface of the printing paper P passing below the air outlet 4oi.

  Further, a wind speed adjusting plate 31 bent into an L shape is attached to the inner surface of the bottom surface portion 4d using an adjusting screw 32. In this case, nuts 33 that can be screwed with adjusting screws 32 from below are fixed to a plurality of positions of the wind speed adjusting plate 31, and long holes 34 through which the adjusting screws 32 are inserted into the bottom surface portion 4d. Is provided. As a result, the adjustment screws 32 are screwed into the nuts 33 through the long holes 34, and the adjustment screws 32 are tightened and loosened to arbitrarily adjust (set) the opening width Lw of the blowing slit 4s. it can. Reference numeral 35 denotes a restriction sheet suspended from the air outlet 4oi, and restricts the blowing direction so that effective cooling of the printing paper P is performed.

  By the way, the selection (setting) of the opening width Lw is important for making the wind speed (air volume) in the width direction Fb of the printing paper P uniform. If the wind speed in the width direction Fb of the printing paper P is not uniform, uneven cooling of the printing paper P will occur, and there is a possibility that a sufficient and reliable prevention effect against the above-described problems such as the blocking phenomenon cannot be obtained. is there. FIG. 5 shows the wind speed with respect to the measurement position along the width direction of the printing paper P. As is apparent from the figure, when the opening width Lw is 1.0 [mm], the deviation of the wind speed with respect to the measurement position is the smallest. If the opening width Lw is further narrower than 1.0 [mm], the wind speed becomes uniform, but there are also harmful effects such as the wind speed being too strong or the air volume being lowered. Therefore, while ensuring the optimum wind speed and air volume, It is desirable to select the opening width Lw at which the wind speed is uniform.

  On the other hand, a sirocco fan 5 s that is thin as a whole and that can suck air (air blow W) from the front in the transport direction Fc of the printing paper P is used as the blower fan 5. As a result, as shown in FIG. 3, even when the sirocco fan 5s is attached to the outer surface (rear surface) of the housing 20, it is possible to avoid the problem of taking in warm air around the fixing unit 75. Moreover, the ventilation duct 11 connects the ventilation nozzle 4 and the ventilation fan 5, and the length and shape of the ventilation duct 11 can be selected arbitrarily. Therefore, the arrangement | positioning site | part of the ventilation fan 5 can be arbitrarily selected by selection of the length and shape of the ventilation duct 11. FIG. In the illustrated embodiment, since the blower fan 5 is attached to the back surface of the housing 20, the blower duct 11 may be a relatively short length without bending. By using such a blower duct 11, it is possible to arbitrarily select the location of the blower fan 5 together with the use of the sirocco fan 5 s, and in particular, the problem of taking in warm air around the fixing unit 75 described above. There is an advantage that it can be surely avoided and that the dead space can be effectively used and the space can be saved by improving the degree of design freedom.

  In the paper discharge mechanism 1 according to this embodiment, if the blower fan 5 is operated during a printing operation, air (blow W) is sucked from the blow fan 5 and the blow W from the blow fan 5 is blown. While being supplied to the ventilation nozzle 4 through the duct 11, it blows off from the ventilation slit 4s (air outlet 4oi). At this time, the blown air W blown from the blower slit 4s is uniform along the width direction Fb of the printing paper P conveyed below the blowout port 4oi and in the entire width range Zb of the printing paper P. Sufficient and uniform cooling can be performed on the entire surface of the conveyed printing paper P. In particular, since it is not necessary to change the conveyance speed of the printing paper P, effective cooling can be performed without sacrificing the printing speed. In addition, since cooling can be performed without being affected by the paper type, it is possible to avoid problems that cause complicated printing paper type discrimination and control by the sensor, and it can be used universally and effectively for plain paper. There are advantages you can do. Note that if the blower unit A is attached to the outer surface (rear surface) of the housing 20 located immediately above the discharge port 2, it is disposed immediately after the discharge roller 21, so that the distance from the printing paper P is stable, and Since the adverse effect on the fixing unit 75 is avoided, the mounting position is the most preferable mounting position.

  FIG. 6 shows measurement data of the surface temperature (upper surface temperature) of the printing paper P with respect to the continuous fixing number (continuous printing number) of the printing paper P. As is apparent from the measurement data, when 50 sheets of plain paper are continuously printed, the surface temperature of the printing paper P is about 90 [° C.] unless the paper discharge mechanism 1 according to the present embodiment is used. In contrast to the high temperature, by using the paper discharge mechanism 1 according to the present embodiment, the temperature can be lowered to about 75 [° C.]. Further, when 50 sheets of thick paper are continuously printed, although the cooling effect is less than that of plain paper, the surface temperature of the printing paper P is about 70 [° C.] if the paper discharge mechanism 1 according to the present embodiment is not used. On the other hand, by using the paper discharge mechanism 1 according to this embodiment, the temperature can be lowered to about 65 [° C.].

  Although the best embodiment has been described in detail above, the present invention is not limited to such an embodiment, and departs from the gist of the present invention in the detailed configuration, shape, material, quantity, numerical value, and the like. It can be changed, added, or deleted as long as it is not.

  For example, although the case where the sirocco fan 5s was used as the blower fan 5 was shown, the blower fin using a general screw fin may be sufficient. Moreover, although the discharge port 2 provided in the housing 20 is shown as the discharge port 2, the discharge port 2 is not necessarily limited to the one provided in the housing 20, and the discharge port provided in the housing 20. 2 may be sufficient. On the other hand, although a pure air cooling type was illustrated, as shown in FIG. 7, the forced cooling part 12 which forcedly cools the ventilation W from the ventilation fan 5 can also be provided. In FIG. 7, a plurality of thermo modules 41 using Peltier elements are attached to the outer surface of the air duct 11 which is relatively long and curved in an L shape, and DC power is supplied to the thermo modules 41. The blower W can be forcibly cooled by the thermo modules 41. Thereby, a cooling effect can be heightened more.

FIG. 3 is a partial cross-sectional side view of the paper discharge mechanism according to the best embodiment of the present invention; Rear view of the cooling mechanism provided in the paper discharge mechanism, Plan view of the cooling mechanism provided in the paper discharge mechanism, A cross-sectional side view of the air blowing slit in the cooling mechanism of the paper discharge mechanism, Characteristic diagram of wind speed against the measurement position in the width direction of printing paper, Characteristic diagram of surface temperature of printing paper against the number of continuous fixings, The rear block diagram of the cooling mechanism part which concerns on the modified embodiment with which the paper discharge mechanism is provided, External perspective view of a printing apparatus provided with the paper discharge mechanism, Schematic configuration diagram of the mechanical system in the printing apparatus, Block diagram of a printing system that connects the printer and computer

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Paper discharge mechanism 2 Outlet 3 Stacker 4 Blowing nozzle 4s Blower slit 5 Blower fan 6 Cooling mechanism part 11 Blower duct 12 Forced cooling part P Printing paper M Printing apparatus Fb Width direction of printing paper Zb Full width range of printing paper W Blowing Lw Opening width

Claims (4)

  In a paper discharge mechanism of a printing apparatus that discharges printed printing paper onto an external stacker through a discharge port, air blown along the width direction of the print paper discharged from the discharge port and to the entire width range of the print paper A paper discharge mechanism for a printing apparatus, comprising a cooling mechanism having a blowing nozzle having a slit and a blowing fan for blowing air to the blowing nozzle.   2. The printing according to claim 1, wherein the cooling mechanism section has a blower duct that connects the blower fan and the blower nozzle in communication with each other, and an arrangement site of the blower fan is selected by the blower duct. The paper discharge mechanism of the device.   The paper discharge mechanism of a printing apparatus according to claim 1, wherein the blower slit has an opening width so that the wind speed in the width direction of the printing paper is uniform.   The discharge mechanism of the printing apparatus according to claim 1, further comprising a forced cooling unit that forcibly cools the air blown from the blower fan.

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