JP4269846B2 - Inkjet image forming apparatus - Google Patents

Description

  The present invention relates to an inkjet image forming apparatus.

  In recent years, the spread of color documents in offices is remarkable, and various output devices have been proposed. Among them, downsizing is possible, and the low-cost inkjet method is used as a powerful recording method in various output devices.

  A print head used in such an ink jet system includes energy generating means, means for converting the energy into ink discharge force, an ink discharge port, and an ink path communicating with the discharge port. Examples of energy generating means include means using an electromechanical transducer such as a piezo element, means for heating ink with an electrothermal transducer having a heating resistor to generate bubbles, and discharging the ink by generating these bubbles, etc. There is.

  The latter print head using an electrothermal conversion element is not only capable of arranging ink discharge ports at a high density because the electrothermal conversion element is small, but also has a semiconductor integrated circuit as a manufacturing technique thereof. Since the manufacturing technique can be diverted, it is possible to reduce the size of the print head having a large number of high-precision ink discharge ports and to manufacture the print head at low cost.

  However, at present, a printing method called serial scan in which printing is performed line by line by moving the print head back and forth while conveying recording paper is mainly used. Although this method can be reduced in size and cost, it has the disadvantage of requiring multiple scans to form an image over the entire paper, resulting in a slower printing speed. It is extremely easy to retract the head to a position that does not face the means for transporting the ink, and the head recovery means that is the fate of the ink jet method (dummy jet mechanism and implementation timing for preventing ink nozzle clogging, in the standby state) There is an advantage that the mounting of the cap for maintaining the ink characteristics, the cleaning of the head, etc.) is easy.

  However, in order to improve the printing speed, it is necessary to reduce the number of scans. For this purpose, it is essential to lengthen the print head. The thing which pushed this to the limit is a printing system having a paper-width printing head, a so-called full line head system.

  Furthermore, as a result of improving the printing speed and pursuing high productivity, a double-sided printer that performs printing on both sides of a recording sheet in one process has been proposed (see, for example, Patent Document 1).

  However, this double-sided printer does not describe the head recovery means, and does not describe the specific method for installing the recovery means. Furthermore, since the original configuration is a single color, if a plurality of recording heads are continuously installed for the purpose of increasing the number of colors, the span between the conveying rollers becomes large and it becomes difficult to stably convey the recording medium. In addition, if the conveying roller is configured between the recording heads, the speed of the recording medium is controlled by the plurality of conveying rollers, so that the recording medium cannot be stably conveyed.

  There has also been proposed a method in which recording heads are opposed to each other to perform double-sided printing, and the recovery means is provided inside both opposing recording heads to bring the heads into contact with each other to recover the recording head (for example, patents). Reference 2).

  However, this method does not solve the problems other than the recovery of the recording head as compared with the above-described method, and has a problem that the transportability deteriorates as the number of colors increases.

  Also, a double-sided printer employing a serial scan printing method has been proposed (see, for example, Patent Document 3). However, in the serial scan, the carriage reciprocates and scans the print surface, so there is a limit to the printing speed. It is difficult to improve productivity.

  Further, a method has been proposed in which the recording medium is conveyed by a conveying belt that holds both ends of the recording medium, and printing is performed on both sides simultaneously (for example, see Patent Document 4).

However, in this method, since only the both ends of the recording medium are held and transported, the transportability is unstable. In particular, in the case of a large-sized recording medium, the behavior of the central portion in the width direction of the recording medium is unstable. The influence of deformation of the recording medium due to absorption is also increased. Further, the mechanism for moving the conveying belt in accordance with the size of the recording medium is complicated, and there are areas where printing cannot be performed at both ends.
Japanese Patent Application Laid-Open No. 10-076713 (FIG. 1, pages 3 to 4) Japanese Patent Laid-Open No. 2001-277528 (FIG. 3, pages 3 to 4) JP 2001-310458 A (FIG. 1, pages 3 to 4) Japanese Patent No. 3305871 (FIG. 14, pages 8 to 9)

  In consideration of the above-described facts, an object of the present invention is to provide a double-sided ink jet image forming apparatus that is small and excellent in recording medium transportability while maintaining high productivity.

The inkjet image forming apparatus according to claim 1, wherein a plurality of first recording heads arranged at a predetermined interval in a direction orthogonal to a direction in which a recording medium is conveyed and a first non-printing between the first recording heads A first conveyance belt disposed in the area along the conveyance direction of the recording medium and conveying the recording medium; a second recording head arranged downstream of the first non-printing area in the recording medium conveyance direction; A second conveyance belt disposed in a second non-printing area between the second recording heads along the conveyance direction of the recording medium and conveying the recording medium, and the first recording The heads are respectively provided on both sides of a conveyance path surface that is a surface through which the recording medium passes when conveyed by the first conveyance belt and the second conveyance belt, and the second recording head is provided on both sides of the conveyance path surface. each provided et al. Characterized in that was.

  In the invention having the above-described configuration, full-line head type double-sided batch printing enables high productivity on both sides, and allows the entire paper to be used as a print area, and a physically divided head. By using a plurality of ink jet heads, the yield in manufacturing the head can be improved, and a low-cost inkjet image forming apparatus can be obtained.

According to a second aspect of the present invention, there is provided the inkjet image forming apparatus according to the first aspect, wherein the print order of the first recording head is a surface side where the recording medium comes into contact with the first conveying belt and then the opposite side. It is characterized by being in order .

  In the invention with the above configuration, it is possible to increase the time until the back surface of the paper comes into contact with the second transport belt when the paper passes from the first transport belt to the second transport belt by printing first from the back surface. Therefore, it is possible to suppress printing blur on the back surface and ink stains on the surface of the second conveyance belt.

  The inkjet image forming apparatus according to claim 3, wherein the driving roller is provided between the first recording head and the second recording head, and the first conveying belt and the second conveying belt are alternately wound around the driving roller. A first driven roller that is provided on the upstream side of the first recording head in the transport direction and on which the first transport belt is wound, and is provided on the downstream side of the second recording head in the transport direction, and the second transport belt And a second driven roller around which is wound.

  In the invention having the above-described configuration, the driving roller for driving the first and second conveying belts is a single common roller, so that the conveying speeds of the first and second conveying belts can be made uniform and stable paper can be obtained. Since conveyance is possible, it is possible to achieve print quality with little color misregistration and density unevenness.

According to a fourth aspect of the present invention, in the configuration of the third aspect, the diameters of the driving roller, the first driven roller, and the second driven roller are the first recording head and the second recording roller. The head is longer than the length in the ink discharge direction.

  In the invention having the above-described configuration, the length of the recording head in the ink discharge direction, that is, the diameters of the driving roller and the driven roller are made larger than the total height, so that the recording head is accommodated in the conveying surfaces of the first and second conveying belts. This eliminates the need to suppress the width of the recording head to be equal to or less than the width of the non-printing area, thus increasing the design flexibility of the recording head.

According to a fifth aspect of the present invention, in the ink jet image forming apparatus according to the third aspect, in addition to the driving roller and the first driven roller, the first conveying belt includes at least the driving roller and the first driven roller. The second conveying belt is wound around a first sub driven roller that is rotatably supported around a rotating shaft that is parallel to and not coplanar with the driving roller and the second driven roller. The rotation of the driving roller is wound around a second sub driven roller that is rotatably supported around a rotation axis that is at least parallel to the rotation axis of the drive roller and the second driven roller and is not on the same plane. The drive roller, the first driven roller, and the first sub driven roller are arranged so that the first recording head is within the moving surface of the first conveying belt as viewed in the axial direction. And the driving roller, the second driven roller, and the second sub driven roller are arranged so that the second recording head is within the moving surface of the second conveying belt when viewed from the rotation axis direction of the driving roller. It is arranged .

In the invention with the above configuration, instead of increasing the diameters of the driving roller and the driven roller, the sub driven roller is arranged in addition to the driven roller and the driving roller , so that recording is performed on the conveying surfaces of the first and second conveying belts. Since the head can be accommodated and the width of the recording head does not need to be suppressed to be equal to or smaller than the width of the non-printing area, the design flexibility of the recording head is increased.

The inkjet image forming apparatus according to claim 6 is the configuration according to any one of claims 1 to 5, wherein the section from the start of printing by the first recording head to the end of printing by the second recording head. The recording medium is conveyed in the vertical direction.

  In the invention with the above configuration, the effect of gravity is made equal on the front and back surfaces by conveying the paper vertically when printing, and the front and back recording heads have the same component configuration and the same settings. Therefore, the cost can be reduced, and the difference in print quality between the front surface and the back surface can be eliminated.

The inkjet image forming apparatus according to claim 7 is the configuration according to any one of claims 1 to 6, wherein the position opposite to the first recording head across the conveyance path surface and the second recording. A recording head recovery means is provided at a position facing the head, respectively .

  In the invention having the above configuration, full-line head type double-sided batch printing is possible, and the recovery operation of the recording head is possible without moving the recording head, so that the entire apparatus can be simplified and downsized. In addition, the recovery operation of the recording head is possible even during continuous printing, and there is no deterioration in image quality or productivity during continuous printing.

  Since the present invention has the above-described configuration, it was possible to provide a double-sided ink jet image forming apparatus that was small and excellent in recording medium transportability while maintaining high productivity.

  1 to 4 show a printing mechanism portion of the inkjet image forming apparatus according to the first embodiment of the present invention.

  FIG. 1 is a perspective view of a printing mechanism portion of the inkjet image forming apparatus according to the first embodiment.

  The ink jet image forming apparatus of the present embodiment is provided with a print recording means 12 corresponding to a long head having a print section divided in the paper width direction.

  The print recording unit 12 is a recording unit that divides a print region in a direction perpendicular to the conveyance direction of the paper 18 (= paper width direction) into a plurality of portions and prints every other divided print region.

  This is a paper width head in which a single row of ink nozzles are arranged as in the past, or a staggered arrangement in the main scanning direction, and the ink nozzles are arranged without gaps in a direction perpendicular to the paper transport direction. Instead of the staggered arrangement head, every other printing area for each recording means is arranged, and the printing area and the non-printing area are alternately arranged in one printing recording means 12. Therefore, in order to cover the entire paper width, at least two print recording means 12 are required for one side of the paper 18.

  In the inkjet image forming apparatus 10 of this embodiment, two print recording means 12 are used for each color of ink on one side of the paper 18, and four print recording means 12 for each color of ink are used to perform double-sided printing. It is necessary to use it.

  For example, in the case of full-color, since the printing recording means 12 for four colors of yellow (Y), magenta (M), cyan (C), and black (K) is necessary, the total apparatus is 8 units per sheet. A total of 16 print recording means 12 are required.

  Y01, M01, C01, K01 to Y12, M12, C12, and K12 in FIG. 2 correspond to the 16 print recording means 12.

  Here, the print recording means 12 that covers and prints the same print area among the print areas divided in the paper width direction is defined as one print set 14. That is, since two print recording means 12 are used for each color on one side of the paper 18 as described above, the number of print sets is also two on one side of the paper 18, for a total of four. That is, Y01 to K02 in FIG. 1 are the upstream side print sets 14 (two front and back), and Y11 to K12 are the downstream side print sets 14 (two back and front).

  The divided print areas in the paper width direction are set at equal intervals. As a result, when the print set 14 is arranged by shifting in the paper width direction by the width of the divided print area at the time of placement in the inkjet image forming apparatus, the print recording means can be used regardless of whether the ink color is single or full color. The same components can be used as the components constituting the component 12, for example, the ink nozzles.

  FIG. 3 shows the relationship between the print recording means 12 and the print area of the paper 18.

  As an example, Y1 color will be described. As shown in FIG. 3A, one side of the sheet 18 is divided into two areas A and B, and Y02, which is Y (yellow) print recording means 12, is located downstream. Y12 is arranged on the side. Y02 which is the print recording means 12 is a set of unit recording heads having a print width WA capable of covering the area A, and similarly Y12 is a set of unit recording heads having a print width WB capable of covering the area B. On Y02, the interval between the unit recording heads in the sheet width direction (= the width of the non-printing area) is set to be equal to or slightly smaller than the printing width WA, and is arranged at equal intervals. Similarly, on Y11, the interval between the unit recording heads in the sheet width direction is set to be equal to or slightly smaller than the printing width WB, and arranged at equal intervals.

  By arranging Y02 and Y12 so as to cover the non-printing areas of the respective printing areas, the printing areas A and B on the paper 18 can be printed without any gaps. Can be an area. At this time, if the interval in the paper width direction between the unit recording heads Y02 and Y12 (= the width of the non-printing area) is set slightly smaller than the printing widths WA and WB, the printing areas of Y02 and Y12 overlap. Generation of white streaks or the like between the print areas A and B can be prevented.

  Further, as shown in FIG. 3B, the unit recording heads of the print recording means 12 for printing the back surface of the paper 18, that is, the surface held by the transport belt 20, are arranged in the gap of the transport belt 20, and the transport belt 20 Is printed on the back side of the paper 18.

  In the case of full color, the above relationship is the same for all of the Y, M, C, and K colors, and in this embodiment, printing is performed on both sides of the paper 18, so that the 16 prints constituting the four print sets 14 are formed. The same relationship holds for all the print recording means 12 (= Y01 to K12).

  Next, a paper conveying method will be described.

  In this embodiment, as shown in FIG. 1, the paper 18 is transported by the transport belt 20 that spans the non-printing area of the printing set 14 described above. Since the non-printing areas are alternately arranged with the printing areas, a plurality of conveying belts 20 are laid at equal intervals in the paper width direction.

  In addition, since the two print sets 14 per one side of the paper 18 are shifted by the width of the region divided in the paper width direction, the arrangement of the conveyor belt 20 is staggered.

  Each group of conveying belts 20 corresponding to each printing set 14 is spanned via one common roller.

  The shared roller is connected to the drive motor 24 directly or through a gear or the like, and serves as a drive roller 26 that is a drive source of each of the conveying belts 20 group. Thereby, the conveyance speed of the upstream and downstream conveyance belts 20 group can be made common (V = constant), and an image failure due to a conveyance speed difference between the upstream and downstream conveyance belts 20 group at the time of paper conveyance can be prevented. The printing quality in the printing set 14 can be stabilized.

  Further, the drive roller 26 has an encoder (not shown) on the roller shaft, and a drive for suppressing rotation unevenness of the drive roller 26 caused by eccentricity of the shaft and gear of the drive motor 24 and the shaft of the drive roller 26. It constitutes a roller control means.

  The control means of the drive roller 26 reads the difference from the ideal rotational speed of the shaft of the drive roller 26, that is, the eccentric error component from the individual encoder signal at the time of rotation, and gives the motor information to cancel the difference. To control eccentricity. At this time, if a stepping motor is used as the drive motor 24, high-performance sheet conveyance control can be performed.

  At the other end of the transport belt 20 group, that is, at the end not on the drive roller 26, the transport belt 20 is held by each driven roller 28.

  As shown in FIG. 4, the driven roller 28 has a steering mechanism 30 and constitutes a conveyance direction control unit that prevents the sheet 18 conveyed on the conveyance belt 20 from meandering.

  When an error in the traveling direction occurs in each belt group, the print image is deteriorated such as image position deviation or streak unevenness. Therefore, a position adjusting means 32 is provided for adjusting the position of the driven roller 28 in the axial direction (= direction perpendicular to the paper transport direction). As an adjustment method, a simple method such as manually adjusting a feed screw, an automatic control method using an actuator, or the like can be considered.

  Further, as shown in FIG. 5A, each roller has a crown-shaped portion where the conveyor belt 20 is stretched, and compared with the conveyance direction of the conveyor belt 20 at the center in the paper width direction, The conveyance direction of the conveyance belt 20 is configured to face outward toward the downstream in the conveyance direction.

  In this embodiment, the tension surface of the conveyor belt 20 of each roller 26, 28 has an appropriate angle. When a so-called flat belt having a normal rectangular cross section is used as the conveying belt 20 as shown in FIG. 5B, the sheet conveying surface A and the surface of the conveying belt 20 coincide with each other according to the angle formed by the stretched surface. As a result, a recess such as A ′ is generated on the sheet conveying surface.

  In the case where the effect of the depressions on the transportability and image quality of the paper 18 is so large that it cannot be ignored, the transport belt 20 stretched at an angle with the transport direction other than the central portion in the paper width direction is shown in FIG. Thus, a so-called V-belt having a cross-sectional shape such that the surface of the conveying belt 20 coincides with the sheet conveying surface A may be used.

  Alternatively, as in the example of FIG. 7, the belt stretching portion 34 of each roller may have a crown shape. In order to turn the conveying direction of both ends in the width direction of the paper 18 outward, the belt stretcher 34 (crown) of the driven roller 28 may be shifted outward with respect to the driving roller 26 in the axial direction. The conveying direction of the conveying belt 20 at both ends is configured to face outward toward the downstream in the conveying direction.

  Alternatively, the rollers may be configured such that the surface speed of the conveyance belt 20 at both ends of the sheet is larger than the surface speed at the center of the sheet (= paper conveyance speed) (V both ends> V center). Thereby, it is possible to prevent image quality deterioration such as a shift in printing position caused by wrinkles or sagging during conveyance of the paper.

  Next, the head recovery means will be described.

  As shown in FIGS. 1 and 2, the head recovery means 36 is arranged at a position facing each print recording means 12 across the conveyance surface of the paper 18. That is, it is disposed at a position where the above-described transport belt 20 is not present.

  The head recovery means 36 has both a cap function for the head for preventing the ejection openings of the ink nozzles from adhering during standby and a dummy jet function for preventing clogging of the ink nozzles.

  As shown in FIG. 8A, when printing on the paper 18, since the paper 18 passes between the print recording means 12 and the head recovery means 36, the surface of the paper 18 facing the head recovery means 36 The head recovery means 36 moves backward (lowers in the figure) to a position where it does not contact.

  As shown in FIG. 8 (b), while the image is not printed, the print recording means 12 is capped to prevent the ink from drying, so that the head recovery means 36 is in close contact with the print recording means 12. The recovery means 36 is moved forward (ascended in the figure).

  As shown in FIG. 8C, a dummy jet is performed as needed in the interval until the printing of the paper 18 is completed and the next paper 18 is conveyed. At that time, the head recovery means 36 moves backward (lowers in the drawing) so as not to interfere with the next paper 18 and receives a dummy jet from the print recording means 12.

  At this time, the moving mechanism of the head recovery means 36 may have an individual mechanism for each head recovery means 36, or each head recovery means 36 is disposed on a common base plate, and the base plate It may be a mechanism that moves itself.

  By arranging the print recording means 12 as described above as the back side, the front side, the back side, and the front side and the front side of the paper 18 as four sets of prints 16, double-sided batch printing on the paper 18 becomes possible. .

  Furthermore, by arranging the head recovery means 36 at a position where the conveyance surface of the paper 18 is sandwiched and avoiding the conveyance conveyance belt 20, the head recovery means 36 can be efficiently mounted while realizing double-sided printing. An inkjet image forming apparatus with high productivity was achieved while avoiding complexity.

  Further, as shown in FIG. 2, the printing order is set to the back side of the paper 18 (the surface that comes into contact with the conveyance belt 20), the front surface, the back side, and the front surface, so Since the sheet surface printed on the upstream side is dried and then contacts the downstream conveying belt 20, ink bleeding and belt contamination due to this contact are less likely to occur.

  Next, a print image printing operation in the above-described configuration will be described.

  The inkjet image forming apparatus 10 (hereinafter referred to as IOT: image output terminal) of the present invention performs image printing based on image data transmitted from image forming apparatus control means (hereinafter referred to as controller) such as a printer controller.

  FIG. 9 shows an operation flow of the inkjet image forming apparatus in the present embodiment.

  When there is no print instruction from the controller, the IOT is in a standby state and the apparatus is stopped. That is, each head recovery means 36 is held in close contact with each head in order to prevent ink deterioration and head clogging.

  First, when printing starts and the controller instructs the IOT to perform a printing operation, in step 40, the IOT lowers each head recovery means 36 and separates each print recording means 12 and each head recovery means 36 so that the paper can be conveyed. Let At this time, the operation of a dummy jet or the like may be performed as necessary before printing.

  In accordance with this, in step 42, the IOT operates the sheet conveying / conveying belt 20. In other words, a starting instruction is issued to the drive roller control means described above, and the drive belt 24 is rotated while the eccentricity control is being performed, thereby driving the conveyor belt 20.

  Next, at step 44, when the rotation of the transport belt 20 is stabilized, the IOT sends out the paper 18 from the paper tray storing the paper and supplies the paper 18 to the transport belt 20.

  A paper leading edge detection sensor is provided on the most upstream side of the conveying belt 20 to detect the leading edge of the paper supplied onto the conveying belt 20. In step 46, printing is sequentially performed on the paper 18 from the most upstream print recording means 12 in accordance with the timing determined based on this detection signal.

  When printing on one sheet 18 is completed, it is determined in step 48 whether or not a dummy jet is necessary according to the time since the power is turned on, the cumulative number of printed sheets, the ink discharge amount, and the like. And do a dummy jet.

  In step 52, when printing by the last (most downstream) print recording means 12 is completed, it is determined whether or not printing of all pages of the paper has been completed, and it is determined that printing of all pages has been completed. The printed paper 18 is discharged out of the apparatus and the printing operation is completed.

  Subsequently, in step 54, when the paper detection sensor disposed at an appropriate location in the IOT detects that the paper 18 is discharged out of the apparatus, or the paper 18 has finished passing the transport belt 20. When this is detected, the drive roller control means stops.

  Thereafter, in step 56, the head recovery means 36 moves forward and caps the head portion of each print recording means 12.

  Thereby, a series of image forming operations is completed.

  With the above configuration, when performing continuous image formation, the dummy jet operation to the head recovery means 36 is performed between the paper 18 and the paper 18 without interrupting the normal printing operation as necessary. (Inter-image section)

  FIG. 10 shows a paper transport portion of an inkjet image forming apparatus according to the second embodiment of the present invention.

  As shown in FIG. 10A, when one or both of the total heights A and B of the print recording means 12 and the recovery means 36 are larger than the vertical width of the conveyance surface of the conveyance belt 20 (= diameter R of the drive roller 26), printing is performed. In order to store the recording unit 12 and the recovery unit 36 in the non-printing area, it is necessary to make the lateral width (width in the direction perpendicular to the paper transport direction) of the printing recording unit 12 and the recovery unit 36 smaller than the width of the non-printing area. .

  In this embodiment, as shown in FIG. 10B, the diameter R of the drive roller 26 that drives the upstream and downstream conveying belts 20 is larger than the total heights A and B of the print recording means 12 and the recovery means 36. large.

  For this reason, since the print recording means 12 and the recovery means 36 fit within the vertical width of the transport surface of the transport belt 20, the lateral width (width in the direction perpendicular to the paper transport direction) of the print recording means 12 and the recovery means 36 is set to the non-printing area. Therefore, it is not necessary to make the width smaller than the width, and the degree of freedom in design can be increased.

  FIG. 11 shows a sheet conveying portion of an inkjet image forming apparatus according to the third embodiment of the present invention.

  In the configuration as shown in FIG. 10B, when the overall height of the print recording unit 12 and the recovery unit 36 is increased, the drive roller 26 having a larger diameter is required, which is disadvantageous in terms of cost and weight.

  As shown in FIG. 11, by adding one small-diameter driven roller 28 in the vicinity of the print recording means 12 to make a total of three rollers, as in FIG. The print recording means 12 fits within the vertical width. Since the recovery means 36 is usually smaller in the vertical width than the print recording means 12, the vicinity of the print recording means 12 is effective for adding the driven roller 28.

  As described above, it is not necessary to make the lateral width (width in the direction perpendicular to the paper conveyance direction) of the print recording means 12 smaller than the width of the non-printing area, so that the degree of freedom in design can be increased.

  FIG. 12 shows a paper transport portion of an inkjet image forming apparatus according to the fourth embodiment of the present invention.

  As shown in FIG. 12, by using two common rollers on the upstream side and the downstream side, one roller can be reduced from the embodiment shown in FIG. 11, which is advantageous in terms of cost and weight. .

  FIG. 13 shows a sheet conveying portion of an inkjet image forming apparatus according to the fourth embodiment of the present invention.

  As shown in FIG. 13, the upstream and downstream conveying belts 20 are supported by a total of six rollers, and two of them are common upstream and downstream rollers, so that the diameter of each roller can be reduced, and the paper is conveyed. The degree of design freedom of the part can be increased.

  FIG. 14 shows a paper transport portion of an inkjet image forming apparatus according to the fifth embodiment of the present invention.

  In each of the embodiments as described above, since the ejection conditions such as the flying speed and the trajectory of the ink droplets are different between the front surface and the back surface of the paper 18 due to the influence of gravity, the setting of the ejection force and the like of the print recording unit 12 is set to the front surface. It needs to be different on the back side.

  Therefore, as shown in FIG. 14, in the paper conveyance section from the start of printing by the print recording means 12 to the end of printing, the print recording means 12 and the recovery means 36 are arranged so that the paper 18 is conveyed in the vertical direction. The components and various settings of the print recording means 12 for the front surface and the back surface of the paper 18 can be made the same.

  As a result, the front and back side print recording means 12 can have the same component configuration and the same settings, so that the cost can be reduced and the difference in print quality between the front and back sides can be eliminated.

  As described above, the full-color ink jet recording apparatus having a plurality of colors capable of full-color printing has been described. However, it goes without saying that the requirements of the present invention can be applied to a recording apparatus having a single color printing recording means instead of full color.

  Also, the inkjet image forming apparatus has been described as a printer that receives print information from outside the image forming apparatus. However, a so-called inkjet type copy that has an image reading apparatus such as a scanner and prints document information read by the image reading apparatus. The effect of the present invention is also effective in the machine.

It is a perspective view which shows the internal structure of the inkjet image forming apparatus which concerns on the 1st form of this invention. 1 is a perspective view showing an internal structure of an inkjet image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a plan view showing a recording head arrangement of the inkjet image forming apparatus according to the first embodiment of the present invention. It is a top view which shows the conveyance mechanism of the inkjet image forming apparatus which concerns on the 1st form of this invention. It is a top view which shows the conveyance mechanism of the inkjet image forming apparatus which concerns on the 1st form of this invention. It is sectional drawing which shows the belt shape of the inkjet image forming apparatus which concerns on the 1st form of this invention. It is a top view which shows the conveyance mechanism of the inkjet image forming apparatus which concerns on the 1st form of this invention. It is a side view which shows the recovery mechanism of the inkjet image forming apparatus which concerns on the 2nd form of this invention. It is a flowchart which shows the printing operation | movement of the inkjet image forming apparatus which concerns on the 1st form of this invention. It is a side view which shows the conveyance mechanism of the inkjet image forming apparatus which concerns on the 2nd form of this invention. It is a side view which shows the conveyance mechanism of the inkjet image forming apparatus which concerns on the 3rd form of this invention. It is a side view which shows the conveyance mechanism of the inkjet image forming apparatus which concerns on the 4th form of this invention. It is a side view which shows the conveyance mechanism of the inkjet image forming apparatus which concerns on the 5th form of this invention. It is a side view which shows the conveyance mechanism of the inkjet image forming apparatus which concerns on the 6th form of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Inkjet image forming apparatus 12 Print recording means 14 Print set 18 Paper 20 Conveying belt 26 Drive roller 28 Driven roller 36 Recovery means

Claims (7)

A plurality of first recording heads arranged at predetermined intervals in a direction perpendicular to the direction in which the recording medium is conveyed;
A first conveying belt that is disposed in a first non-printing area between the first recording heads along a conveying direction of the recording medium and that conveys the recording medium;
A second recording head arranged downstream of the first non-printing area in the recording medium conveyance direction;
A second non-printing area between the second recording heads, a second conveying belt disposed along the conveying direction of the recording medium and conveying the recording medium;
The first recording heads are respectively provided on both sides of a conveyance path surface that is a surface through which the recording medium passes when conveyed by the first conveyance belt and the second conveyance belt;
The inkjet image forming apparatus, wherein the second recording head is provided on each side of the conveyance path surface .   2. The inkjet image forming apparatus according to claim 1, wherein a printing order of the first recording head is an order of a surface side where the recording medium comes into contact with the first conveying belt and then an opposite side. A driving roller provided between the first recording head and the second recording head, wherein the first conveying belt and the second conveying belt are alternately wound;
A first driven roller provided on the upstream side of the first recording head in the transport direction and around which the first transport belt is wound;
A second driven roller provided on the downstream side in the transport direction of the second recording head and around which the second transport belt is wound;
The inkjet image forming apparatus according to claim 1, wherein the inkjet image forming apparatus is provided.   The diameter of the said driving roller, the said 1st driven roller, and the said 2nd driven roller is larger than the length in the ink discharge direction of the said 1st recording head and the said 2nd recording head, The Claim 3 characterized by the above-mentioned. Inkjet image forming apparatus. In addition to the driving roller and the first driven roller, the first conveying belt is supported so as to be rotatable around a rotating shaft that is at least parallel to and not on the same plane as the driving roller and the first driven roller. Wound around the first sub driven roller
In addition to the driving roller and the second driven roller, the second conveying belt is supported so as to be rotatable around a rotating shaft that is parallel to and not on the same plane as at least the driving roller and the second driven roller. Wound around the second sub driven roller
The driving roller, the first driven roller, and the first sub driven roller are arranged so that the first recording head is within the moving surface of the first conveying belt when viewed from the rotation axis direction of the driving roller, The driving roller, the second driven roller, and the second sub driven roller are arranged so that the second recording head is within the moving surface of the second conveying belt when viewed from the rotation axis direction of the driving roller. The inkjet image forming apparatus according to claim 3.   6. The recording medium according to claim 1, wherein the recording medium is conveyed in a vertical direction in a section from the start of printing by the first recording head to the end of printing by the second recording head. Inkjet image forming apparatus. 7. The recording head recovery means is provided at a position facing the first recording head and a position facing the second recording head across the transport path surface, respectively . 2. An inkjet image forming apparatus according to item 1.

Images