JP2008290370A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which can continue printing with one inkjet engine while the other one is under ink head maintenance or recovery operation, or in failure, and yet is small-sized, and lightweight. <P>SOLUTION: The image forming apparatus 1 of the present invention is provided with: a printing section 3 having a plurality of inkjet engines 23a and 23b each having an ink head 25; a feed conveying passage 5 for conveying a recording medium 2 to a printing area 4; and a discharge conveying route 7 for conveying the recording medium 2 from the printing region 4. The plurality of inkjet engines 23a and 23b are arranged side by side in a direction orthogonal to the conveying direction of the recording medium 2 so that they cross the conveying passage of the recording medium 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that forms an image by ejecting ink from an ink head.

  In Patent Document 1, a plurality of image forming units equipped with an ink jet engine are arranged in a stack, and the ink jet engine of one image forming unit can be continuously used even if maintenance is required due to a mechanical failure or the like. This is disclosed.

  Patent Document 2 discloses an image forming apparatus that performs recording on both sides of a recording medium by disposing an inkjet engine on both sides of the recording medium.

JP 2005-161654 A JP 2003-136743 A

  However, the image forming apparatus described in Patent Document 1 has a problem in that the size of the image forming apparatus increases because all of the stacked image forming units include an inkjet engine and a transport mechanism.

  The image forming apparatus described in Patent Document 2 includes two inkjet engines. Each inkjet engine is used for printing on the front and back of the paper. Therefore, for example, when there is a need for maintenance due to a mechanical failure or the like in an inkjet engine that prints on the surface of a sheet, printing on the surface is forced to be interrupted.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a small and lightweight image forming apparatus that can continue printing with the other inkjet engine during maintenance / recovery operation or failure of the ink head of one inkjet engine. And

  In order to solve the above problems, the invention described in claim 1 is a printing unit including a plurality of inkjet engines having ink heads, a supply conveyance path for conveying a recording medium to a printing area, and a recording medium from the printing area. A plurality of inkjet engines arranged side by side in a direction perpendicular to the conveyance direction of the recording medium so as to cross the conveyance path of the recording medium.

  The invention described in claim 2 is characterized in that, in the invention described in claim 1, a drive mechanism is provided for moving the printing unit in a direction perpendicular to the conveyance direction of the recording medium.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, a printing unit mounting portion is provided on at least one side of the housing of the image forming apparatus, and the printing unit is removed from the mounting unit. It is characterized by being detachable.

  According to a fourth aspect of the invention, there is provided an ink head maintenance / recovery mechanism according to the first aspect of the invention, wherein at least one ink head maintenance / recovery mechanism is disposed on both sides of the recording medium conveyance path. It is characterized by being.

  According to a fifth aspect of the present invention, in the first aspect of the present invention, the recording medium is wound in a roll shape, and the recording medium is drawn from the roll body and supplied to the supply conveyance path.

  According to a sixth aspect of the present invention, in the fifth aspect of the present invention, a supply-side tension relaxation portion that relaxes the tension in the conveyance direction of the recording medium is provided in the supply conveyance path.

  The invention described in claim 7 is, in the invention described in claim 6, provided with a winding mechanism for continuously winding the recording medium downstream of the discharge conveying path in the conveying direction of the recording medium. It is characterized by.

  The invention described in claim 8 is characterized in that, in the invention described in claim 7, a discharge side tension relaxation portion for relaxing tension in the conveyance direction of the recording medium is provided in the discharge conveyance path.

  The invention described in claim 9 is characterized in that, in the invention described in claim 5, a cutter for cutting the recording medium is provided in the supply conveyance path.

  According to a tenth aspect of the present invention, in the sixth aspect of the present invention, the discharge conveyance path is provided with a discharge-side tension relaxation portion that loosens the recording medium, and the recording medium is disposed downstream of the discharge-side tension relaxation portion. A cutter for cutting is provided.

  According to the present invention, while printing with one inkjet engine, the other inkjet engine can perform maintenance / recovery operation or maintenance such as repair, while one inkjet engine is in maintenance / recovery operation. During maintenance, printing can be performed with the other inkjet engine, so that there is no downtime due to the inkjet engine being down, and printing efficiency is good. Furthermore, since the printing unit includes a plurality of inkjet engines that can move to the printing area and there is no need to separately provide a recording medium transport mechanism or the like, the image forming apparatus can be reduced in size and weight.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view illustrating a schematic configuration around a printing unit of the image forming apparatus according to the first embodiment, FIG. 2 is a perspective view of the image forming apparatus, and FIG. 3 is a cross-sectional view illustrating movement of the inkjet engine. FIG. 4 is a perspective view of a line-type inkjet engine, and FIG. 5 is a cross-sectional view showing a schematic configuration of the image forming apparatus.

  The image forming apparatus 1 according to the first embodiment is a printer that forms an image by an inkjet recording method.

  The image forming apparatus 1 includes a printing unit 3, a supply conveyance path 5 that conveys a recording medium (paper) 2 to the printing unit 3, a discharge conveyance path 7 that conveys the printed recording medium 2 from the printing unit 3, and a housing. 6 and a drive mechanism 45 for the inkjet engines 23a and 23b. The image forming apparatus 1 includes a paper feed cassette (recording medium storage unit) 9, a paper discharge tray (recording medium discharge unit) 11, an ink tank 13, and ink that supplies ink from the ink tank 13 to the printing unit 3. A path 15 is also provided.

  As shown in FIG. 2, the casing 6 has a substantially rectangular parallelepiped box shape, and the recording medium 2 is transported into the casing from the one end face side 17 a of the printing unit 3 toward the other end face side 17 b. As described above, the supply conveyance path 5 and the discharge conveyance path 7 are continuously formed, and the mounting portion 19 of the printing unit 3 is provided between the supply conveyance path 5 and the discharge conveyance path 7. In the casing, a maintenance / recovery mechanism 61 for the ink head 25 is provided on both sides of the recording medium conveyance path.

  As shown in FIG. 2, the mounting unit 19 can be attached and detached by inserting and removing the printing unit 3 in a direction perpendicular to the conveyance direction of the recording medium 2.

  The two inkjet engines 23 a and 23 b are arranged side by side in a direction perpendicular to the conveyance direction of the recording medium 2, and are surrounded by a frame 43 and fixed to one. These two inkjet engines 23 a and 23 b can be moved together in a direction perpendicular to the conveyance direction of the recording medium 2 by a drive mechanism 45. This movement is performed so that when one inkjet engine 23a is in the print area 4, the other inkjet engine 23b is in a position outside the print area 4, and the other inkjet engine 23b is in the print area 4. Is performed so that one of the inkjet engines 23 a is located at a position outside the print region 4.

  The ink jet engines 23a and 23b are line type ink jet recording type ink jet engines using an ink jet recording head corresponding to the width of the recording medium 2. The ink jet engines 23a and 23b are composed of a line type liquid ejecting head for ejecting liquid droplets in an engine housing. There are 25 ink heads for each color. The ink head portion has a nozzle row in which nozzles for discharging droplets are arranged over a substantially entire length of the paper. The inkjet engines 23a and 23b include a recording medium transport mechanism 29 including a transport belt 27 and a motor 28 that transport the recording medium 2 in a direction orthogonal to the nozzle rows of the recording head unit. On the lower surface of the ink head, an ink head having a predetermined number of ejection ports is provided for each color of Y (yellow), M (magenta), C (cyan), and K (black). The line-type ink jet can convey and print a recording medium without intermittent driving, and can increase the printing speed.

  The conveyance belt 27 is driven in the conveyance direction of the recording medium 2 by rotating the drive shaft 33 by the motor 31.

  As shown in FIG. 2, a handle 37 is provided on one side surface parallel to the conveyance direction of the case 35 of the printing unit 3 so that the printing unit 3 can be inserted and removed in a direction perpendicular to the conveyance direction of the recording medium 2. ing. An ink tank 13 is detachable from the image forming apparatus 1 in the same direction as the ink jet engines 23a and 23b next to the ink jet engines 23a and 23b so that ink or ink cassettes can be replenished. . The printing unit 3 includes a recording medium transport mechanism 29 below the inkjet engines 23a and 23b.

  In the printing unit 3, an intake port 39 for taking in the recording medium 2 is formed on the end surface of the supply conveyance path, and a discharge port 41 for discharging the recording medium 2 is formed on the end surface of the discharge conveyance path.

  As shown in FIG. 3, the drive mechanism 45 includes a conveyance belt 47, a conveyance roller 49, a motor 51, a sensor 53 that detects the temperature of the ink head 25 and the environmental temperature, and a control device 55. The inkjet engines 23a and 23b are disposed on the transport belt 47, and can move in a direction perpendicular to the transport direction in conjunction with the movement of the transport belt 47. The conveyance belt 47 moves in the rotation direction of the conveyance roller 49, and the conveyance roller 49 moves clockwise or counterclockwise by the driving force of the motor 51 at the timing calculated by the control device 55 that receives the signal from the sensor 53. It has become.

  The control device 55 includes a detection unit 57 and a drive control unit 59. The detection unit 57 detects data obtained by analyzing information from the sensor 53, and the drive control unit 59 maintains / maintains the ink head 25 based on this data. The recovery time, the rotation speed and the rotation direction of the motor 51 are determined.

  The maintenance / recovery mechanism 61 of the ink head 25 is disposed on both sides of the recording medium conveyance path. Each maintenance / recovery mechanism 61 is disposed at a position where it can be joined to the ink head 25. A porous body is inserted into the maintenance / recovery mechanism 61 so that the ink does not fall off when the suction recovery operation is executed. The material of this porous body is not specified, but it is sufficient if it has no reactivity with ink and can absorb ink instantaneously. The maintenance / recovery mechanism 61 has an opening 63 that receives periodic preliminary discharge during printing.

  When printing is performed with the ink head 25, a well-known preliminary discharge is performed in the inkjet as a means for preventing drying of unused nozzles. Preliminary ejection is largely related to the nozzle configuration of the recording head and the physical properties of the ink, and varies depending on the recording system. In this embodiment, a sensor 53 that detects the head temperature and the environmental temperature of the ink head 25 is provided, and the preliminary ejection time during printing is set based on the temperature.

  For example, in the vicinity of the room temperature, the discharge is performed every several tens of seconds, and when the temperature is lower than the room temperature, the preliminary discharge is performed at intervals of about half the time. The time setting should be changed according to the nozzle diameter and ink physical properties.

  The ink head 25 performs preliminary ejection unrelated to printing during printing at regular intervals through the opening 63 of the maintenance / recovery mechanism 61. The ink accumulated in the maintenance / recovery mechanism 61 is idled according to the volume of the unit. This is performed in consideration of the size, number of ink droplets, and ink physical properties of the flying ink droplets.

  It has been found that when the ink head 25 ejects ink for a printing operation, unnecessary bubble silence or ink wetting on the head face surface occurs in the head, thereby degrading the print quality. For this reason, a recovery operation with suction is set after a predetermined print quantity has been implemented.

  The two inkjet engines 23a and 23b alternately perform maintenance / recovery operations. The recovery operation is performed as necessary. The recovery means includes a wiper means (not shown) for removing ink on the head face surface in addition to the suction pump.

  Next, functions and effects of the image forming apparatus 1 according to the first embodiment will be described.

  According to the image forming apparatus 1 according to the present embodiment, the recording medium 2 is sent from the paper feed cassette 9 to the supply conveyance path 5 by the paper feed roller 21, and the intake port 39 on the side surface of the case 35 of the printing unit. The print area 4 is reached by the recording medium transport mechanism 29 of the printing unit 3. The printed recording medium 2 passes through the discharge port 41 on the side surface of the case 35 of the printing unit 3, is sent to the discharge conveyance path 7, and is discharged to the discharge tray 11.

  In the printing unit 3, the inkjet engines 23 a and 23 b can be moved by a drive mechanism 45 in a direction perpendicular to the transport direction as necessary. As a result, while one inkjet engine 23a is printing in the printing area 4, the other inkjet engine 23b is maintained / recovered by the maintenance / recovery mechanism 61 at a position outside the printing area 4 or repaired. It is possible to perform maintenance such as. While the other ink jet engine 23b is printing in the print area 4, one ink jet engine 23a can perform a maintenance / recovery operation or the like outside the print area. That is, there is no downtime due to the convenience of the inkjet engines 23a and 23b, and a large amount of printing can be performed continuously and speedily. Further, since the ink jet engines 23a and 23b can be easily taken out from the image forming apparatus 1, maintenance and replacement can be easily performed when the ink jet engines 23a and 23b fail.

  According to the present invention, while printing with one inkjet engine, the other inkjet engine can perform maintenance / recovery operation or maintenance such as repair, while one inkjet engine is in maintenance / recovery operation. During maintenance, printing can be performed with the other inkjet engine, so that there is no downtime due to the inkjet engine being down, and printing efficiency is good. Furthermore, since the printing unit includes a plurality of inkjet engines that can move to the printing area and there is no need to separately provide a recording medium transport mechanism or the like, the image forming apparatus can be reduced in size and weight.

  In the present embodiment, by using line-type heads for the inkjet engines 23a and 23b, printing can be performed without intermittently driving the recording paper, so that the printing speed can be increased and high-productivity images can be achieved. A forming apparatus can be provided. Further, since the printing unit 3 includes the recording medium transport mechanism 29, the positional relationship between the transport mechanism 29 and the inkjet engines 23a and 23b can be maintained with high accuracy.

  Other embodiments of the present invention will be described below. In the following description, parts having the same operational effects as those of the first embodiment described above are denoted by the same reference numerals, and the parts thereof are described. Detailed description will be omitted, and the following description will mainly focus on differences from the first embodiment described above.

  FIG. 6 shows a second embodiment. In the second embodiment, the recording medium transport mechanism 29 is provided separately from the printing unit 3. For this reason, since the printing unit 3 can be reduced in size, the printing unit 3 can be easily replaced.

  FIG. 7 shows a third embodiment. In the third embodiment, the image forming apparatus 1 uses the recording medium 2 wound around the roll body 67, and includes a winding mechanism 68 that winds the recording medium 2 downstream of the printing unit 3. Yes. The recording medium 2 taken up by the roll body 67 is pulled out and conveyed along the supply conveyance path 5, and reaches the printing area 4 by the conveyance mechanism 29 of the printing unit 3. The recording medium 2 after printing is transported along the discharge transport path 7 and is wound into a roll again by the winding mechanism 68.

  A supply-side tension relaxation unit 70 is provided in the supply conveyance path 5. The supply side tension relaxation unit 70 is provided with conveyance rollers 69 and 74 of the recording medium 2 at a predetermined interval on the upstream side and the downstream side of the supply conveyance path 5, and is located on the downstream side of the upstream conveyance roller 69. By slowing down the rotation speed of the transport roller 74, the recording medium 2 is slackened. The transport rollers 69 and 74 are each composed of two upper and lower rollers, and transport the recording medium 2 so as to sandwich the recording medium 2 vertically. A discharge-side tension relaxation portion 72 is provided in the discharge conveyance path 7. The discharge side tension relaxation unit 72 is provided with conveyance rollers 76 and 78 on the upstream side and the downstream side of the discharge conveyance path, and makes the recording medium 2 slack, like the supply side tension relaxation unit 70.

  According to the third embodiment, a series of recording can be performed continuously. Further, the tension of the recording medium 2 taken up by the roll body 67 and the tension of the recording medium 2 taken up by the take-up mechanism 68 are applied to the conveying roller 69 and the discharge conveying path 7 provided on the upstream side of the supply conveying path 5. By receiving by the conveyance roller 78 provided on the downstream side, a load fluctuation to the conveyance mechanism 29 of the printing unit 3 caused by a change in tension acting on the recording medium 2 can be prevented, and a good image can be recorded. .

  FIG. 8 shows a fourth embodiment. In the fourth embodiment, the image forming apparatus 1 uses the recording medium 2 wound around the roll body 67, and the recording medium 2 wound around the roll body 67 is drawn out and supplied to the supply conveyance path. 5 is cut by a cutter 71 provided at 5, conveyed along the supply conveyance path 5, and reaches the printing region 4 from the conveyance mechanism 29 of the printing unit 3. The recording medium 2 after printing is discharged to the paper discharge tray 11 along the discharge conveyance path 7. The cutter 71 is composed of a pair of blades provided above and below the supply conveyance path, and cuts the recording medium 2 so as to sandwich the recording medium 2 vertically.

  According to the fourth embodiment, since the recording medium 2 wound around the roll body 68 is cut to a predetermined length before printing, the change in the tension of the recording medium 2 wound around the roll body 67 is changed. The load fluctuation due to is not exerted on the transport mechanism 29 of the printing unit 3, and a good image can be recorded.

  FIG. 9 shows a fifth embodiment. The fifth embodiment is characterized in that, in the third embodiment, the cutter 71 is provided on the downstream side of the discharge-side tension relaxation portion 72 and the paper discharge tray 11 is provided in place of the winding mechanism 68. The recording medium 2 after printing is conveyed by the discharge conveyance path 7, cut to a predetermined length by the cutter 71, and discharged to the paper discharge tray 11.

  The supply conveyance path 5 is provided with a supply-side tension relaxation unit 70 to prevent a load variation due to a change in tension of the recording medium 2 wound around the roll body 67. The discharge conveyance path 7 is provided with a discharge-side tension relaxation portion 72. When the recording medium 2 wound around the roll body 68 is cut by the cutter 71, the tension acting on the recording medium changes, and printing is performed. It is possible to prevent a load variation from being applied to the transport mechanism 29 of the section 3. Since the discharge-side tension relaxation portion 72 is provided, it is possible to continue the conveyance and printing of the recording medium 2 even when the recording medium is being cut by the cutter 71, thereby improving the printing efficiency. it can.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, the line type ink jet engines 23a and 23b may be serial ink jet engines. By using a popular and inexpensive serial type head, an image forming apparatus can be provided at a low price.

  As shown in FIG. 10, the printing unit 73 having a serial type ink jet engine includes a carriage 75, a guide member (not shown) for guiding the carriage 75 in the main scanning direction, and the carriage in the main scanning direction along the guide member. A main scanning motor 77 to be moved, a conveying belt 27 for conveying a recording medium, and a conveying roller 28 are provided. Ink is supplied from the ink tank 13 to the carriage 75. The output end of the main scanning motor 77 is connected to the carriage 75 via a timing belt 79, and is converted into a linear motion to move the carriage 75 in the main scanning direction.

  In addition to surrounding the two inkjet engines 23a and 23b with the frame 43 as in the first embodiment, one inkjet engine 23a is provided with a fitting projection, and the other inkjet engine 23b is formed with a fitting recess. Alternatively, the two inkjet engines 23a and 23b may be connected with each other. The inkjet engines 23a and 23b can be accurately positioned at the time of connection, and the inkjet engines 23a and 23b can be connected with high accuracy and workability is good.

  Further, the ink jet engines 23a and 23b may be added. For example, in the case of using four inkjet engines, if one set of two adjacent inkjet engines is used for color and the other adjacent set is used for monochrome, the inkjet engines are selectively used according to the recorded image. be able to.

  As shown in FIG. 3, in the first embodiment, the two inkjet engines 23 a and 23 b move in a row and come out of the mounting portion 19, but the directions in which the inkjet engines 23 a and 23 b are separated from each other. It is also possible to adopt a configuration in which it is moved away from the opposite side surfaces of the case 35 of the printing unit 3. Further, a configuration in which three or more ink jet engines move and disconnect is possible.

  The plurality of inkjet engines may be inkjet engines having different resolutions. Depending on the resolution of the recorded image, an inkjet engine that is not used for printing can be maintained and recovered, and an inkjet engine can be added if necessary to improve the resolution. It is possible to continue.

FIG. 2 is a cross-sectional view illustrating a schematic configuration around a printing unit of the image forming apparatus according to the first embodiment. 1 is a perspective view of an image forming apparatus according to a first embodiment. It is sectional drawing which shows the movement of an inkjet engine. It is a perspective view which shows the external appearance of a printing part provided with a line type inkjet engine. 1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to a first embodiment. It is sectional drawing which shows schematic structure of the image forming apparatus which concerns on 2nd Embodiment. It is sectional drawing which shows the outline of the image forming apparatus which concerns on 3rd Embodiment. It is sectional drawing which shows the outline of the image forming apparatus which concerns on 4th Embodiment. It is sectional drawing which shows the outline of the image forming apparatus which concerns on 5th Embodiment. It is a perspective view which shows the external appearance of a printing part provided with the serial type inkjet engine which concerns on the modification of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Recording medium 3 Printing part 4 Printing area 5 Supply conveyance path 6 Housing | casing of image forming apparatus 7 Discharge conveyance path 19 Mounting part of a printing part 23a One inkjet engine 23b The other inkjet engine 25 Ink head 37 Supply conveyance Path 39 discharge conveyance path 45 drive mechanism 61 maintenance / recovery mechanism 67 roll body 68 take-up mechanism 70 supply side tension relaxation part 71 cutter 72 discharge side tension relaxation part

Claims (10)

  A printing unit including a plurality of inkjet engines having ink heads, a supply conveyance path for conveying a recording medium to a printing area, and a discharge conveyance path for conveying the recording medium from the printing area. An image forming apparatus, wherein the image forming apparatuses are arranged in a direction perpendicular to the conveyance direction of the recording medium so as to cross the conveyance path.   The image forming apparatus according to claim 1, further comprising a drive mechanism that moves the printing unit in a direction perpendicular to the conveyance direction of the recording medium.   The image forming apparatus according to claim 1, wherein a mounting portion for the printing unit is provided on at least one side surface of the housing of the image forming apparatus, and the printing unit is detachable by inserting and removing the printing unit from the mounting unit. apparatus.   The image forming apparatus according to claim 1, further comprising an ink head maintaining / recovering mechanism, wherein at least one ink head maintaining / recovering mechanism is disposed on both sides of the recording medium conveyance path. .   The image forming apparatus according to claim 1, wherein the recording medium is wound in a roll shape, and the recording medium is pulled out from the roll body and supplied to the supply conveyance path.   The image forming apparatus according to claim 5, wherein a supply-side tension relaxation unit that relaxes a tension in a conveyance direction of the recording medium is provided in the supply conveyance path.   The image forming apparatus according to claim 6, further comprising a winding mechanism for continuously winding the recording medium downstream of the discharge conveying path in the recording medium conveying direction.   The image forming apparatus according to claim 7, wherein a discharge-side tension relaxation portion that relaxes a tension in a conveyance direction of the recording medium is provided in the discharge conveyance path.   6. The image forming apparatus according to claim 5, wherein a cutter for cutting the recording medium is provided in the supply conveyance path.   The image forming apparatus according to claim 6, wherein a discharge-side tension relaxation portion that loosens the recording medium is provided in the discharge conveyance path, and a cutter that cuts the recording medium is provided downstream of the discharge-side tension relaxation portion. apparatus.

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