JP2006069162A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus comprising an inkjet print section capable of preventing image formation time from prolonging without having any effect on a required image formation matter. <P>SOLUTION: In the image forming apparatus 1 comprising an inkjet print section 5 having a recording head 26 and a stencil print section 4 and forming a stencil print image 28 and/or an inkjet print image 30 on a sheet 2, the inkjet print section 5 performs idle ejection of ink from the recording head 26 irrespectively of the inkjet print image 30 when the stencil print image 28 and the inkjet print image 30 are formed on the sheet 2 wherein the idle ejection is carried out during inter-sheet time, i.e. the time interval after passage of the rear end of a preceding sheet 2 for forming an image through the recording head 26 before arrival of the forward end of a following sheet 2 at the recording head 26. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus capable of performing both image formation by a stencil printing method and image formation by an ink jet recording method.

  After a plate cylinder composed of a porous support cylinder and a master having a laminate structure in which a porous support is bonded to a thermoplastic resin film, the surface of the thermoplastic resin film of the master is heated and perforated by a thermal head. Wrapped around the plate cylinder, an appropriate amount of ink is supplied to the inner peripheral surface of the plate cylinder by ink supply means provided inside the plate cylinder, and the paper is pressed against the outer peripheral surface of the plate cylinder by pressing means such as a press roller or an impression cylinder. Thus, there is known a digital thermal stencil printing apparatus that performs printing by transferring ink oozed from a plate cylinder opening part and a master punching part onto a sheet. Such a stencil printing apparatus is mainly used when a large number of tens or more of the same image is required. This is because the cost per printed material is low and high-speed printing is possible, so that a large number of printed materials can be obtained in a short time.

  However, stencil printing always requires a plate (master) for printing, so if you want to print a small amount of one or several sheets, or if you want to print only a few different images for each of several tens of identical images. Cannot handle when you want to print. In addition, when printing corresponding to a plurality of originals and making them into a booklet, a collation operation is required after the printing operation, and an image like a copying apparatus capable of repeatedly outputting different original images in page order. There is a problem that it cannot respond to formation.

  Therefore, an image forming apparatus using a plateless image forming method such as an electrophotographic method or an ink jet method is more suitable for forming a small amount of various images. An image forming apparatus using a stencil printing method is more suitable. As described above, since the image forming apparatus has advantages and disadvantages according to the required image, it is necessary for the user who performs image formation to use them separately. However, if each type of image forming apparatus is held, the cost and installation are different. Since each space is doubled, it is usually necessary to use only an image forming apparatus corresponding to image formation that is frequently used. Therefore, an image forming apparatus including a stencil printing unit and an ink jet printing unit is described in, for example, “Patent Document 1” and “Patent Document 2”.

  In the image forming apparatus provided with the above-described ink jet printing unit, in order to prevent nozzle clogging due to drying of the ink caused by leaving the recording head unused for a predetermined time, the ink nozzle is separated from the image forming operation. It is necessary to periodically perform the operation of idle discharge. However, since this idle ejection is performed at an idle ejection position different from the normal image forming position, the image forming operation is interrupted while the recording head occupies the idle ejection position, and the overall image formation time becomes longer. There is a problem that.

  Therefore, for example, “Patent Document 3” discloses a technique of performing idle ejection at an image forming position where a recording head faces a sheet on which image formation is performed. According to this technique, since the idle ejection is performed on the sheet when the recording head occupies the image forming position, the stop time of the image forming operation during the movement of the recording head to the idle ejection position is omitted. Therefore, it is possible to prevent the image formation time from being prolonged.

JP 2002-137514 A JP 2003-334993 A JP-A-6-15815

  However, since the technique disclosed in “Patent Document 3” performs blank ejection on a sheet on which an image is formed, unnecessary characters and patterns formed at the time of blank ejection are mixed in a necessary image. There is a problem that. This greatly impairs the image forming quality, and becomes a serious problem in an important document or an image formed product requiring an aesthetic sense.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus provided with an ink jet printing section that solves the above-described problems and can prevent an increase in image forming time without affecting a required image formed product. And

  According to a first aspect of the present invention, there is provided an image forming apparatus that includes an ink jet printing unit having a recording head and a stencil printing unit, and forms an ink jet print image and / or a stencil print image on a paper. When forming an image and an ink jet print image, the ink jet printing unit performs an empty discharge for discharging ink from the recording head regardless of the ink jet print image at an image forming position. After the trailing edge of the preceding paper to be made has passed through the recording head, it is performed during the inter-paper time until the leading edge of the succeeding paper reaches the recording head.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect of the present invention, the image forming apparatus further includes an interval adjusting unit that adjusts the interval of the time between sheets.

  According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the interval adjusting unit further changes an image forming speed in the stencil printing unit.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the second aspect, the interval adjusting unit further skips the image formation in the stencil printing unit.

  According to a fifth aspect of the present invention, there is provided an image forming apparatus that includes an ink jet printing unit having a recording head and forms an ink jet printing image on a sheet. The ink jet printing unit is separated from the recording head regardless of the ink jet printing image. The idle ejection for ejecting ink is performed at the image forming position. This idle ejection is performed after the trailing edge of the preceding paper on which image formation is performed passes through the recording head, and then the leading edge of the succeeding paper is applied to the recording head. It is characterized in that it is performed at the time between sheets, which is until it reaches.

  According to a sixth aspect of the present invention, in the image forming apparatus according to the fifth aspect of the present invention, the image forming apparatus further includes an interval adjusting unit that adjusts the interval between the sheets.

  According to the present invention, after the trailing edge of the preceding sheet on which image formation is performed passes through the recording head, the idle ejection is performed during the interval between sheets until the leading end of the succeeding sheet reaches the recording head. By doing so, it is possible to perform idle ejection without affecting the image forming operation, and it is possible to continuously obtain a good image formed product while preventing a long image forming time. In addition, the interval adjusting unit can perform idle ejection without affecting the image forming operation under any conditions, and can increase the image forming time regardless of the image formation. It is possible to continuously obtain a good image formed product while preventing it.

  FIG. 1 shows an image forming apparatus employing one embodiment of the present invention. In FIG. 1, an image forming apparatus 1 includes a paper feeding unit 3 that feeds paper 2, a stencil printing unit 4 that performs stencil printing on the paper 2 fed from the paper feeding unit 3, and an inkjet image on the paper 2. An ink jet printing unit 5 for forming the paper, a paper discharge unit 6 for discharging the image-formed paper 2 to the outside of the apparatus, and the like.

  The paper feed unit 3 includes a paper feed tray 10 on which a large number of papers 2 are stacked, a paper feed roller 11 that feeds the paper 2 on the paper feed tray 10 from the uppermost one by one, and a paper feed roller 11. A registration roller pair 12 and the like are provided that temporarily stops the fed paper 2 and then feeds the paper 2 toward the stencil printing unit 4 at a predetermined timing. The paper feed tray 10 is provided with a plurality of paper size detection sensors 61 for detecting the size of the paper 2 stacked on the upper surface thereof. The paper feed roller 11 and the registration roller pair 12 are rotationally driven by separate drive means (not shown), and these drive means (not shown) are driven in synchronization with the rotation timing of the plate cylinder 20 described later.

  A plate making unit 7 is disposed on the upper right side of the stencil printing unit 4. The plate making section 7 cuts a master accommodating section 14 that accommodates a master 13 wound in a roll shape, a thermal head 15 and a platen roller 16 that are disposed downstream of the master accommodating section 14 in the master transport direction, and the master 13. A master cutting means 17, a master conveying roller pair 18 for nipping and conveying the master, and the like. The plate making unit 7 forms a perforated plate making image on the master 13, and then conveys the plate making master 19 toward the stencil printing unit 4.

  The stencil printing unit 4 is provided so as to be able to contact with and separate from a plate cylinder 20 made of a porous cylinder that winds the master-making master 19 made by the plate-making unit 7 on the outer peripheral surface, and the outer peripheral surface of the plate cylinder 20. A press roller 22; a peeling claw 23 for peeling the paper 2 from the outer peripheral surface of the plate cylinder 20; a belt transporting section 25 for transporting the peeled paper 2 while sucking it onto the belt surface by a suction fan 24; . An ink supply means 9 having an ink roller 21 and a doctor roller 8 is disposed inside the plate cylinder 20. The stencil printing unit 4 supplies the paper 2 fed from the paper feeding unit 3 to the pre-printed master 19 wound on the outer peripheral surface of the plate cylinder 20 by the press roller 22, thereby supplying from the ink supply unit 9. The ink thus transferred is transferred to the paper 2 to form a stencil image on the paper 2. On the upper left side of the plate cylinder 20, a plate removal device (not shown) that peels and discards the used master 19 from the outer peripheral surface of the plate cylinder 20 is disposed.

  The plate cylinder 20 is rotationally driven by a speed variable motor (not shown), and the rotational peripheral speed of the plate cylinder 20 is configured to be variable according to a set printing speed. Further, the belt conveyance unit 25 that conveys the paper 2 on which the stencil image is transferred by the plate cylinder 20 is set so that the conveyance speed of the paper 2 is slightly higher than the printing speed, and the printing speed has changed. It is configured to change accordingly.

  The ink jet printing unit 5 includes an ink jet recording head 26 disposed above the transport path of the paper 2, a pair of paper transport rollers 27 and 29 disposed on the upstream and downstream sides in the paper transport direction of the ink jet recording head 26, and the paper to be transported. 2, a lower guide plate 31 for guiding 2, a paper detection sensor 32 for detecting the leading end of the paper 2 in the transport direction and setting a start reference for inkjet printing on the paper 2. Each pair of paper transport rollers 27 and 29 transports the paper 2 at the same paper transport speed as the belt transport unit 25. The paper conveyance speed at this time changes according to the printing speed.

  In each pair of paper transport rollers 27 and 29, the roller positioned above the paper transport path is in direct contact with the stencil image formed on the paper 2, so that the peripheral surface is finely protected to prevent stains due to undried ink. It is desirable to use those having unevenness. Specifically, it is effective to attach a film or the like in which fine ceramic abrasive grains or fine glass beads are scattered on the circumferential surface of the roller.

  The ink jet recording head 26 is configured to be movable in a paper width direction orthogonal to the paper transport direction by a moving mechanism 36. As shown in FIG. 2, a holding portion 71 that is guided by a guide rail 70 provided on a frame 75 and is movable in the paper width direction, which is the left-right direction in the figure, is integrally provided on the upper portion of the inkjet recording head 26. It has been. A lead screw 73 is screwed into the ink jet recording head 26, and when the lead screw 73 is rotationally driven by a stepping motor 72 provided on the frame 75, the ink jet recording head 26 is moved in the paper width direction. . The position of the inkjet recording head 26 is detected by a home position sensor 74 provided on the guide rail 70 and detecting the initial position of the inkjet recording head 26 and the number of steps of the stepping motor 72. In the drawing, reference numeral 76 denotes a removable ink container, reference numeral 77 denotes an ink delivery pump, reference numeral 78 denotes an ink transport pipe, and reference numeral H denotes the ink jet recording head 26 in the paper width direction. The image formable length is shown.

  The moving mechanism 36 described above moves and adjusts the position of the inkjet print image formed on the paper 2 in the paper width direction. The position of the inkjet print image formed on the sheet 2 in the sheet conveyance direction is adjusted and moved according to the operation timing of the inkjet recording head 26. The ink jet recording head 26 receives image data sent from a personal computer 45 (see FIG. 6) connected to the image forming apparatus 1 or a variable data recording memory 48 (see FIG. 6) provided inside the image forming apparatus 1. Based on this, image formation is performed. Further, the stencil printing unit 4 moves and adjusts the position of the stencil printing image formed on the paper 2, that is, the position of the paper 2 with respect to the plate making image of the master-making master 19 wound on the outer peripheral surface of the plate cylinder 20. A moving mechanism (not shown) is provided. As the moving mechanism (not shown), for example, the same moving mechanisms 80 and 280 disclosed in JP-A-9-104159 can be used.

  In FIG. 3, the image formable length in the paper width direction of the inkjet recording head 26 is H, and the plate making length in the paper width direction of the stencil printing unit 4 is K. Usually, the plate making length K is set to about 290 mm in order to enable A3 size stencil printing. However, if the image formable length H is the same as this, the inkjet recording head 26 becomes very expensive. Therefore, in this embodiment, in order to make the inkjet recording head 26 inexpensive, the image formable length H is set to about 60 to 100 mm. In this image forming apparatus 1, the part where the ink jet recording head 26 wants to form an image is a part of the entire image such as the addressed part or the serial number part. is there. 3, reference numeral 28 indicates a stencil print image formed on the paper 2, and reference numeral 30 indicates an ink jet print image formed on the paper 2.

  As shown in FIG. 4, an opening 31 a is formed in the lower guide plate 31. The opening 31a is formed to have a length corresponding to the distance from one movement limit of the inkjet recording head 26 shown by a solid line in FIG. 4 to the other movement limit of the inkjet recording head 26 shown by a two-dot chain line in FIG. Below that, a waste ink tank (not shown) is disposed. The ink jet recording head 26 is configured to be able to perform idle ejection at the image forming position, and ink ejected from the nozzles of the inkjet recording head 26 by idle ejection passes through the opening 31a and is not shown in a waste ink tank. Stored inside.

  A paper discharge unit 6 is disposed on the downstream side of the inkjet printing unit 5 in the paper conveyance direction. The paper discharge unit 6 is transported by the belt transport unit 34 and the belt transport unit 34 that transport the paper 2 on which the image is formed in the stencil printing unit 4 and / or the ink jet printing unit 5 while sucking the paper 2 on the belt surface by the suction fan 33. And a paper discharge tray 35 on which the image-formed paper 2 is stacked.

  An image reading unit 40 is disposed above the stencil printing unit 4. The image reading unit 40 has a known configuration including a movable scanning unit 41 that reads an image on the document 42, an image sensor 43 such as a CCD to which image data scanned by the scanning unit 41 is input, and the like.

  FIG. 5 shows an operation panel of the image forming apparatus 1. In the figure, the operation panel 50 is disposed on the upper front surface of the apparatus main body of the image forming apparatus 1. The operation panel 50 includes a plate making start key 51, a print start key 52, a trial printing key 53, a stop key 54, a ten key 55, a clear key 56, a display device 57 including a 7-segment LED, a display device 58 including an LCD, and four directions. A key 59, a print switching key 60, a printing speed setting key 62, and the like are provided. Various numerical values are entered in the display device 57, and the display device 58 has a hierarchical structure and displays various information. The four-way key 59 has an up key 59a, a down key 59b, a left key 59c, and a right key 59d, and is used for various settings. The print switching key 60 is a select switch, and image formation by the image forming apparatus 1 is performed for image formation by only the stencil printing unit 4, image formation by only the ink jet printing unit 5, image formation by the stencil printing unit 4 and the ink jet printing unit 5. Selectively switch to either. The printing speed setting key 62 has keys 62a and 62b for increasing / decreasing the printing speed. When the key 62a is pressed, the printing speed is decreased, and when the key 62b is pressed, the printing speed is increased. The image forming apparatus 1 shown in the present embodiment has 1 to 5 printing speeds, and an appropriate speed is selected from these speeds.

  FIG. 6 is a control block diagram relating to image processing of the image forming apparatus 1. The image forming apparatus 1 shown in the present embodiment includes an image processing device 37 inside the apparatus main body, and common image data read by the image reading unit 40 and image-formed by the stencil printing unit 4 is the image processing device 37. After the predetermined image processing is performed in the common image data processing device 38, the image data is sent to the thermal head drive control device 44 via the image forming unit selection means 39 in the image processing device 37, and based on this data. Then, each heating element of the thermal head 15 selectively generates heat, and the master 13 is punched.

  On the other hand, the variable image data sent from the personal computer 45 and subjected to image formation in the inkjet printing unit 5 is subjected to predetermined image processing by the variable image data processing device 46 and then passed through the image forming unit selection means 39. Based on this data, the ink jet recording head 26 selectively ejects ink to form an image based on this data. Alternatively, the variable image data sent from the variable data recording memory 48 in which necessary image data is recorded in advance is sent to the ink jet head driving device 47 via the image forming unit selecting means 39, and the ink jet is based on this data. The recording head 26 selectively ejects ink to form an image. The operation of the ink jet recording head 26 with respect to the conveyed paper 2 is controlled by a recording head positioning drive control device 49.

  FIG. 7 is a control block diagram relating to the idle ejection operation of the image forming apparatus 1. In the figure, a control means 63 comprising a known microcomputer receives signals from the operation panel 50 and the paper size detection sensor 61, and based on these signals, a variable speed motor (not shown) for rotating the plate cylinder 20 and paper feeding. Signals are output to the unit 3, the belt conveyance units 25 and 34, the paper conveyance roller pairs 27 and 29, and the inkjet head driving device 47.

  Based on the above-described configuration, the operation of forming a stencil print image and an inkjet print image on the paper 2 using the image forming apparatus 1 in the present embodiment will be described below. The operator switches the print switching key 60 on the operation panel 50 to the “inkjet + stencil” position, sets the document 42 in the image reading unit 40, and presses the plate making start key 51. When the plate making start key 51 is pressed, the scanning unit 41 scans the image of the document 42 and sends this data to the image sensor 43, and a plate discharging device (not shown) is activated to be used from the outer peripheral surface of the plate cylinder 20. The master-making master 19 is peeled off. After completion of the plate removal operation, the plate cylinder 20 rotates to a predetermined plate supply standby position and stops, and a clamper (not shown) provided on the outer peripheral surface is opened to enter a plate supply standby state.

  When the plate cylinder 20 enters a plate feed standby state, the platen roller 16 and the master transport roller pair 18 are operated to send out the master 13. The sent master 13 is punched and made based on the image data sent to the image sensor 43 when passing through the thermal head 15. The master 13, which has been subjected to plate making and becomes a plate-made master 19, is clamped by a clamper of the plate cylinder 20, and then the plate cylinder 20 is driven to rotate at the same peripheral speed as the conveying speed of the master 13. It is wound on the outer peripheral surface. When the master 13 for one plate is conveyed, the master cutting means 17 is actuated to cut the master 13 and the winding operation is completed.

  After the winding operation is completed, the paper feed roller 11 is operated to feed one sheet 2 from the paper feed tray 10, and the plate cylinder 20 is rotated at a low speed. The fed paper 2 is temporarily stopped by the registration roller pair 12 and then fed between the plate cylinder 20 and the press roller 22 at a predetermined timing. Then, the press roller 22 is swung at a predetermined timing, and the paper 2 is brought into pressure contact with the plate-making master 19 wound on the outer peripheral surface of the plate cylinder 20. The ink supplied to the inner peripheral surface of the plate cylinder 20 by the ink roller 21 by this pressure contact is transferred to the paper 2 through the opening portion of the plate cylinder 20 and the perforated portion of the master 19 and the so-called printing operation is performed. Done. The sheet 2 to which the stencil printing image, which is the printing image, is transferred by the printing operation is peeled off from the plate-making master 19 on the plate cylinder 20 by the peeling claw 23 and then sent to the belt transport unit 25 and further downstream. It is conveyed.

  The sheet 2 sent by the belt conveyance unit 25 is conveyed to the ink jet printing unit 5 by the sheet conveyance roller pair 27. During this printing operation, the inkjet printing unit 5 does not perform image formation, and the sheet 2 on which the printing image has been transferred is conveyed further downstream by the sheet conveying roller pair 29 and discharged via the belt conveying unit 34. It is discharged onto the tray 35.

  When the trial printing key 53 is pressed by the operator after the printing operation in the stencil printing unit 4 is completed, the sheet feeding roller 11 is activated to feed one sheet 2 from the sheet feeding tray 10. The plate cylinder 20 is rotationally driven at a rotational peripheral speed corresponding to the printing speed set by the printing speed setting key 62. The fed paper 2 is timed by the registration roller pair 12 and then sent between the plate cylinder 20 and the press roller 22, and the stencil printing image is transferred by the press roller 22 swinging. . Thereafter, the sheet 2 is conveyed by the belt conveying unit 25 and the sheet conveying roller pair 27, and when the leading end is detected by the sheet detection sensor 32, the inkjet is performed based on the image data sent from the personal computer 45 or the variable data recording memory 48. The recording head 26 operates and an ink jet print image is formed on the upper surface thereof. The sheet 2 on which the stencil printing image and the inkjet printing image are formed is further conveyed by the sheet conveying roller pair 29 and the belt conveying unit 34 and is discharged onto the sheet discharge tray 35.

  After the position or density of each image is confirmed by the above-described test printing operation, when the print start key 52 is pressed after the number of images formed on the display device 57 is set by the operator, the paper feed roller 11 is activated. Then, the paper 2 is continuously fed from the paper feed tray 10 and the plate cylinder 20 is rotationally driven at a rotational peripheral speed corresponding to the printing speed set by the printing speed setting key 62, during the trial printing operation. The image forming operation is performed in the same manner as described above. When the set number of image forming sheets is consumed, the operation of the image forming apparatus 1 is stopped, and the image forming apparatus 1 again enters the image forming standby state.

  In the image forming apparatus 1 shown in the present embodiment, the idle ejection for ejecting the old ink accumulated in the nozzles of the inkjet recording head 26 is the time between sheets during the printing operation, that is, the trailing edge of the preceding sheet 2 is the inkjet recording head. After passing through 26, this is performed at predetermined intervals in the time until the leading edge of the subsequent paper 2 reaches the inkjet recording head 26. The inter-paper time is grasped by the control means 63 based on the signal from the paper detection sensor 32, and the signal is output from the control means 63 to the ink jet head drive device 47 during the inter-paper time when the idle ejection is performed. The ink jet head driving device 47 drives the ink jet recording head 26 based on the idle ejection image data stored in advance in the data recording memory 48, and ink is ejected from the nozzles of the ink jet recording head 26. During this time between sheets, the sheet 2 does not exist on the lower guide plate 31, and the ink ejected idle is stored in a waste ink tank (not shown) through the opening 31a.

  According to the above-described configuration, after the trailing edge of the preceding sheet 2 passes through the inkjet recording head 26, a predetermined time is required for the time between sheets until the leading edge of the succeeding sheet 2 reaches the inkjet recording head 26. By performing idle ejection for each period, it is possible to continuously obtain a good image formation while preventing the image formation time from being prolonged by performing idle ejection without affecting the image forming operation.

  In the present embodiment, the idle ejection is performed between the sheets 2, and therefore, the interval between sheets, that is, the time during which the sheet 2 can be ejected according to the size of the sheet 2 and the rotational peripheral speed of the plate cylinder 20 as the printing speed, that is, on the lower guide plate 31 The time for which the opening 31a and the inkjet recording head 26 face each other without the sheet 2 is changed. For this reason, when the paper 2 to be used is a large size (for example, A3 size) and the printing speed is fast (for example, 120 rpm), the time between the papers becomes too short and the idle ejection must be performed. There are cases where idle discharge cannot be performed at certain times. In this case, the control means 63 functions as an interval adjusting means, and the sheet conveying speed of each of the sheet conveying roller pairs 27 and 29 is generated so that the time when the sheet 2 does not exist on the lower guide plate 31 is generated for the time necessary for idle ejection. And the printing speed, which is the image forming speed, is changed so as to match the paper conveyance speed, and the speed variable motor (not shown), the paper feeding unit 3, the belt conveyance units 25 and 34, and the respective paper conveyance roller pairs 27 and 29 are calculated. Control the operation of This control is performed only at the timing when the idle ejection must be performed, and other operations are performed according to the set printing speed.

  By the operation of the control means 63, it is possible to perform idle ejection without affecting the image forming operation under any conditions, and to increase the image forming time regardless of the image forming. It is possible to continuously obtain a good image formed product while preventing it.

  In the above-described example, the control unit 63 is configured to change the printing speed by controlling the operation of the speed variable motor (not shown), the paper feeding unit 3, the belt conveyance units 25 and 34, and the pair of paper conveyance rollers 27 and 29. However, instead of this, while the plate cylinder 20 rotates a plurality of times, the operation of the paper feeding unit 3 is controlled so as to perform skip paper feeding for feeding the paper 2 once, and the image forming operation in the stencil printing unit 4 The time between sheets may be adjusted by skipping.

  In the above embodiment, the case where a stencil image and an ink jet print image are formed on the paper 2 is shown, but only the ink jet print image is formed on the paper 2 by switching the print switching key 60 to the “inkjet” position. The present invention may be applied to. In this case, the adjustment of the time between sheets may be performed by changing the image forming speed or by skipping paper feeding as described above. Further, the control means 63 functioning as the interval adjusting means may control only the operation of each pair of paper transport rollers 27 and 29.

1 is a schematic front view of an image forming apparatus employing an embodiment of the present invention. It is the schematic of the inkjet printing part used for one Embodiment of this invention. It is a figure for demonstrating the image range of the stencil printing part and inkjet printing part in one Embodiment of this invention. It is the schematic for demonstrating the operation | movement of idle discharge in one Embodiment of this invention. It is the schematic of the operation panel used for one Embodiment of this invention. FIG. 3 is a control block diagram relating to image processing of the image forming apparatus used in an embodiment of the present invention. FIG. 4 is a control block diagram relating to an idle ejection operation of an image forming apparatus used in an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Paper 4 Stencil printing part 5 Inkjet printing part 26 Recording head (inkjet recording head)
28 Stencil Printing Image 30 Inkjet Printing Image 63 Spacing Adjustment Unit (Control Unit)

Claims (6)

In an image forming apparatus that includes an inkjet printing unit having a recording head and a stencil printing unit, and forms an inkjet printing image and / or a stencil printing image on paper,
When forming a stencil print image and an ink jet print image on a sheet, the ink jet printing unit performs empty discharge for discharging ink from the recording head at the image forming position regardless of the ink jet print image. The ejection is performed during the interval between sheets after the trailing edge of the preceding sheet on which image formation is performed passes through the recording head and until the leading edge of the succeeding sheet reaches the recording head. A featured image forming apparatus. The image forming apparatus according to claim 1.
An image forming apparatus comprising interval adjusting means for adjusting the interval of the time between sheets. The image forming apparatus according to claim 2.
The image forming apparatus according to claim 1, wherein the interval adjusting means changes an image forming speed in the stencil printing unit. The image forming apparatus according to claim 2.
The image forming apparatus according to claim 1, wherein the interval adjusting unit skips image formation in the stencil printing unit. In an image forming apparatus that includes an ink jet printing unit having a recording head and forms an ink jet print image on paper,
The ink jet printing unit performs idle ejection for ejecting ink from the recording head at an image forming position regardless of the ink jet print image, and the trailing edge of the preceding paper on which image formation is performed is performed on the recording head. An image forming apparatus characterized in that the image forming apparatus is performed during a time between sheets after the sheet passes through and before the leading edge of the succeeding sheet reaches the recording head. The image forming apparatus according to claim 5.
An image forming apparatus comprising interval adjusting means for adjusting the interval of the time between sheets.

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