JP2005067025A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device which can effectively utilize a double-sided recording mechanism. <P>SOLUTION: At the time of one side printing, it is judged in accordance with an ink residual quantity or failure whether or not a recording head for front and a recording head for rear can be used (104). The recording head is changed over in accordance with whether or not it can be used (110, 118, 120 and 122). Moreover, in the case when a face up instruction is present, printing is carried out by using the recording head for front (106-110). When a face instruction is not present, a recording head management table is read, and printing by the recording head for front and printing by the recording head for rear are changed over to make use frequencies uniform in accordance with the use frequency of each recording head (110 and 114-118). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus capable of forming an image on both sides of a recording medium.

  In the market of image forming apparatuses such as printers, there is an urgent need to pursue high productivity of image forming apparatuses, and many applications have been filed for image forming apparatuses that form images on both sides of recording paper.

  For example, in the technique described in Patent Document 1, a front surface printing head for printing on the front surface of a printing paper and a back surface printing head for printing on the back surface of the printing paper are provided. It has been proposed to print on both sides of the printing paper by simultaneously driving the front surface printing head and the back surface printing head during staying in the printing paper. This shortens the time for double-sided printing and eliminates the troublesome work of setting photographic paper twice in the printer apparatus.

  In addition to this, technologies such as Patent Document 2, Patent Document 3, and Patent Document 4 have been proposed as recording heads provided on both surfaces of a recording sheet so that both surfaces can be recorded simultaneously.

  Patent Document 2 proposes a double-sided printer that employs a serial scan printing method. In the technique described in Patent Document 2, a recording cartridge provided with a recording head and an ink recovery device is arranged on the front and back surfaces of a recording sheet. However, duplex printing is possible.

  Patent Document 3 also discloses a printer that performs double-sided printing with the recording heads facing each other and the recovery means is provided inside both the recording heads facing each other so that the heads come into contact with each other to recover the recording heads. Proposed. In the technique disclosed in Patent Document 3, two recording heads are arranged so that nozzle rows extend in directions orthogonal to the paper transport direction, and these nozzle rows face each other across the paper transport path. In this way, the length of the nozzle row is set to a length that sufficiently satisfies the width of the paper, and the front and back of the paper are simultaneously recorded while the paper is being conveyed.

Further, Patent Document 4 proposes a method in which a recording medium is conveyed by a conveying belt that holds both ends of the recording medium and printing is performed on both sides simultaneously.
Japanese Patent Application Laid-Open No. 10-077613 JP 2001-310458 A JP 2001-277528 A Japanese Patent No. 3305871

  However, in the techniques described in Patent Documents 1 to 4 described above, recording heads are provided on both sides of the recording medium, but the function is not effectively used during single-sided printing or the like. For example, when one of the recording heads is broken or the ink is emptied, there is a problem that printing cannot be performed when printing on the corresponding side even with single-sided printing.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an image forming apparatus capable of effectively using a double-sided recording mechanism.

  In order to achieve the above object, the invention described in claim 1 includes a first recording unit that records an image on one side of a recording medium, a second recording unit that records an image on the other side of the recording medium, In order to record an image on a recording medium, switching means for switching driving to at least one of the first recording means and the second recording means, and when recording an image on one side of the recording medium, the first recording means And control means for controlling the drive switching by the switching means based on the state of the second recording means.

  According to the first aspect of the invention, the first recording unit records an image on one side of the recording medium, and the second recording unit records the image on the other side of the recording medium. In the switching means, the drive is switched to at least one of the first recording means and the second recording means. That is, by switching the drive of the switching means, an image can be recorded on one side of the recording medium using one of the first recording means and the second recording means, and on both sides of the recording medium by using both recording means. Images can be recorded collectively.

  In the control means, when the image is recorded on one side of the recording medium, the drive switching by the switching means is controlled based on the states of the first recording means and the second recording means. As a result, when one recording unit becomes unusable, the other recording unit can record an image, and the double-sided recording mechanism can be used effectively.

  For example, as in the invention described in claim 2, by further comprising a detecting means for detecting the states of the first recording means and the second recording means, the recording means that is automatically used based on the state of each recording means Can be switched.

  As the detecting means, as in the third aspect of the invention, the availability of the first recording means and the second recording means may be detected. For example, the failure of the first recording means and the second recording means may be detected as availability as in the invention described in claim 4, or the availability is determined as in invention of claim 5. The remaining amount of ink may be detected.

  Further, as the detection means, the use frequency of the first recording means and the second recording means may be detected as in the sixth aspect of the invention. In this case, as in the seventh aspect of the invention, the drive switching by the switching unit may be controlled so that the usage frequencies of both the recording units are equal.

  As in the invention described in claim 8, the control means controls the drive switching by the switching means in accordance with the ink remaining amount of the first recording means and the second recording means, so that the ink of one recording means is discharged. Even if it disappears, image recording can be performed by the other recording means.

  Further, in the invention according to any one of claims 1 to 8, as in the invention according to claim 9, the state of the first recording means and the second recording means (for example, failure, out of ink, etc.). ) May be further provided, and the control means may control the drive switching by the switching means in accordance with the input of the input means.

  Furthermore, the invention according to any one of claims 1 to 9 further includes an instruction means for instructing the front and back of a recording medium on which an image is recorded, as in the invention according to claim 10. The control unit may control drive switching by the switching unit in accordance with an instruction from the instruction unit.

  As described above, according to the present invention, when an image is recorded on one side of a recording medium, the drive switching is performed based on the state of the first recording means and the second recording means, whereby the image by one recording means. Since the other recording means can be used when recording is not possible, the double-sided printing mechanism can be effectively used.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view of an inkjet image forming apparatus 10 according to an embodiment of the present invention, and FIG. 2 is a plan view of the inkjet image forming apparatus 10 according to an embodiment of the present invention. 2 is a view of FIG. 1 as viewed from above.

  The inkjet image forming apparatus 10 is provided with a long head having a printing unit divided in the paper width direction, and each printing unit is a printing recording means 12.

  The print recording unit 12 divides a print area in a direction (paper width direction) perpendicular to the conveyance direction of the paper 18 into a plurality of prints, and prints every other divided print area.

  This is a conventional paper width head in which a single row of ink nozzles is arranged, 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 print area for each print recording means 12 is arranged, and for the paper 18 width, the print area (placement area of the print recording means 12) and the non-print area are alternately arranged. It has been configured. Therefore, at least two rows of print recording means 12 are necessary to cover the entire paper width.

  In the inkjet image forming apparatus 10 according to the present embodiment, the print recording means 12 is used in two rows for each ink color. For example, in the case of a full color, the print recording means 12 for four colors of yellow (Y), magenta (M), cyan (C), and black (K) is necessary. 12 is required. Y0, Y1, M0, M1, C0, C1, K0, and K1 in FIG. 2 correspond to the eight rows of 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, as described above, since the print recording means 12 of two rows per color is used, the print set 14 also has two rows. That is, Y0, M0, C0, and K0 in FIG. 2 are the upstream side print set 14, and Y1, M1, C1, and K1 are the downstream side print set 14.

  The divided print areas in the paper width direction are set at equal intervals. Accordingly, 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 10, print recording can be performed regardless of whether the ink color is single color or full color. The same parts can be used as the parts constituting the means 12, for example, the ink nozzles.

  Next, the configuration of the paper transport system will be described.

  In the present embodiment, the sheet is transported by the transport belt 20 that spans the non-printing region of the above-described two-row printing set 14. 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.

  Further, since the two print sets 14 are arranged so as to be shifted by the width of the region divided in the paper width direction, the arrangement of the conveying belt 20 is staggered.

  Each group of conveying belts 20 corresponding to the printing sets 14 in each row is spanned via one common roller.

  The common roller is connected to the drive motor 24 through a straight line or a gear, and serves as a drive roller 26 that is a drive source of each of the conveying belts 20 group. As a result, the transport speeds of the upstream and downstream transport belts 20 group can be made common, image failure due to the transport speed difference between the upstream and downstream transport belts 20 group during paper transport can be prevented, and printing by the print set 14 can be performed. The quality 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 roller 26 and the shaft of the drive roller 26. Roller control is performed.

  In the drive roller control, the difference from the ideal rotation speed of the shaft of the drive roller 26, that is, the eccentric error component is read from the individual encoder signal at the time of rotation, and information for canceling it is given to the motor. The eccentricity is controlled. At this time, a stepping motor can be used as the drive motor 24. By using the stepping motor, high-performance sheet conveyance control can be performed.

  At the other end of the conveyance belt 20 group, that is, at the end not on the drive roller 26, the conveyance belt 20 is held by each driven roller 28. The driven roller 28 has a steering mechanism (not shown) and performs conveyance direction control so that the paper 18 conveyed on the conveyance belt 20 does not meander.

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

  Each roller has a crown-shaped portion where the conveying belt 20 is stretched, and the conveying direction of the conveying belt 20 at both ends is downstream of the conveying direction compared to the conveying direction of the conveying belt 20 at the center in the paper width direction. It is configured to face outward.

  In the present embodiment, the stretching surface of the conveyance belt 20 of each roller has an appropriate angle, and when the depression of the sheet conveyance surface caused by this angle cannot be ignored, the conveyance belts 20 at both ends are Also, a so-called V-belt having a cross-sectional shape whose surface coincides with the sheet conveyance surface may be used.

  Next, the head recovery means 16 for maintenance of the print recording means 12 will be described.

  The head recovery means 16 is disposed at a position facing each print recording means 12 with the paper conveyance surface interposed therebetween. That is, it is disposed at a position where the above-described conveyor belt 20 is not present.

  The head recovery means 16 has both a head cap function 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.

  When printing on the paper 18, since the paper 18 passes between the print recording means 12 and the head recovery means 16, the head recovery means 16 reaches a position where it does not contact the surface of the paper 18 facing the head recovery means 16. Retreats.

  While the image is not printed, the head is capped to prevent the ink from drying, and therefore the head recovery means 16 is advanced when the head recovery means 16 comes into close contact with the head. At this time, the moving mechanism of the head recovery means 16 may have an individual mechanism for each head recovery means 16, or each head recovery means 16 is disposed on a common base plate, and the base plate itself A moving mechanism may be applied.

  In the inkjet image forming apparatus 10 according to the present embodiment, the print recording unit 12 as described above is arranged on the back surface, the front surface, the back surface, the front surface and the four rows of print sets 14 so as to face both surfaces of the paper 18. Thus, it is possible to perform double-sided batch printing on the paper 18 and printing on only the front surface or the back surface. In the following description, the two rows of print sets 14 on the back side are referred to as the back recording head 22B (see FIG. 3), and the two rows of print sets 14 on the front side are referred to as the front recording head 22A (see FIG. 3).

  Further, since the head recovery means 16 is arranged at a position where the conveyance surface of the paper 18 is sandwiched to avoid the conveyance belt 20, the head recovery means 16 can be efficiently mounted while realizing double-sided printing, The inkjet image forming apparatus 10 with high productivity can be obtained while avoiding complexity.

  Also, by setting the printing order to the back side of the paper (the surface that comes into contact with the transport belt 20), the front surface, the back surface, and the front surface, the printed paper surface comes into contact with the transport belt 20 after drying. Bleeding and belt contamination are less likely to occur.

  Next, the configuration of the control system of the inkjet image forming apparatus 10 according to the embodiment of the present invention will be described. FIG. 3 is a block diagram showing the configuration of the control system of the inkjet image forming apparatus 10 according to the embodiment of the present invention.

  In the inkjet image forming apparatus 10, operations such as a printing operation are controlled by the controller 30. The controller 30 is composed of a microcomputer including a CPU, ROM, RAM, peripheral devices, and the like, and various programs for operating the inkjet image forming apparatus are stored in the ROM of the controller 30. By starting, the operation of the inkjet image forming apparatus 10 is controlled.

  In addition, an operation panel 32 is connected to the controller 30, and various instructions such as start and stop of a printing operation can be performed by a user performing an operation input to the operation panel 32.

  Further, the controller 30 is connected to the front recording head 22A and the rear recording head 22B, which are composed of the above-described two-row print set 14, via the head drivers 34A and 34B, and to the paper via the motor driver 36. The controller 30 is connected to a drive motor 24, and the controller 30 controls the driving of the front recording head, the rear recording head, and the motor driver 24 to perform a printing operation.

  For example, when the controller 30 receives print data from an external computer or the like via a network or the like, the controller 30 decodes a print instruction included in the print data, and the front recording head 22A and the back side according to whether double-sided printing or single-sided printing is performed. In addition to controlling the ejection of ink from the recording head 22B, the drive motor 24 is driven to control the conveyance of the paper. As a result, an image based on the print data can be formed on the paper 18.

  The inkjet image forming apparatus 10 according to the present embodiment can instruct the operation panel 32 to face up (front side printing) or face down (back side printing), and the switching is performed by the controller 30. Since the face-up and face-down are performed by switching the recording heads 22A and 22B used by the controller 30 without inverting the front and back of the paper 18, the configuration of the paper transport system can be simplified.

  Further, the controller 30 includes a failure detection unit 38 that detects a failure of each recording head 22A, 22B, an ink remaining amount detection unit 40 that detects a remaining amount of ink in each recording head 22A, 22B, and each recording head 22A, 22B. A recording head management table 42 for managing the usage status and various sensors 44 such as a sensor for detecting the leading edge of the paper provided on the uppermost stream side or the paper discharge side of the conveyor belt 20 are connected.

  The failure detection means 38 detects a failure of the front recording head 22A and the back recording head 22B, and the controller 30 determines whether or not each recording head 22A, 22B can be used based on the detection result. The controller 30 performs drive switching between the front recording head 22A and the back recording head 22B in accordance with the availability. Note that the failure detection of the recording heads 22A and 22B may be manually confirmed by the user, and may be input via an operation panel or the like when a failure has occurred.

  The ink remaining amount detecting means 40 detects the ink remaining amount of the print recording means 12 constituting each recording head 22A, 22B and outputs the detection result to the controller 30. The controller 30 Based on the detection result of the amount detection means 40, it is determined whether or not printing by each of the recording heads 22A and 22B is possible. When it is determined that printing by one recording head is impossible, the controller 30 prints an image using the other recording head in the case of single-sided printing.

  In addition, the recording head management table 42 stores the usage status of the front recording head 22A and the back recording head 22B, such as the number of times of use (total image amount and printed page). Based on the usage status of each of the recording heads 22A and 22B stored in the recording head management table 42, driving of the front recording head 22A and the back recording head 22B is switched. In the present embodiment, the controller 30 switches the driving of the recording heads 22A and 22B so that the usage frequencies of the front recording head 22A and the back recording head 22B are substantially equal.

  Next, print control of the inkjet image forming apparatus 10 configured as described above will be described with reference to FIG. FIG. 4 is a flowchart showing the flow of printing control of the inkjet image forming apparatus 10 according to the embodiment of the present invention.

  First, in step 100, the controller 30 determines whether or not to start printing. This determination is made by determining whether or not a print request has been made to the inkjet image forming apparatus 10 from an external computer or the like via a network or the like.

  In step 102, the controller 30 determines whether or not the print request is double-sided printing. If the determination is negative, the process proceeds to step 104.

  In step 104, the controller 30 determines whether or not both recording heads (front recording head 22A and back recording head 22B) can be used. The determination can be made based on the detection result of the failure detection means 38, whether each recording head 22A, 22B operates normally, and the remaining ink amount of each recording head 22A, 22B from the detection result of the remaining ink detection means 40. If the determination is affirmative, the process proceeds to step 106.

  In step 106, the controller 30 determines whether or not there is a face instruction. The determination is made, for example, by determining whether a face-up or face-down instruction is in the print request, or whether a face-up or face-down instruction is input via the operation panel 32. If the determination is affirmative, the routine proceeds to step 108.

  In step 108, it is determined whether or not the face instruction is face up. If the determination is affirmative, the routine proceeds to step 110.

  In step 110, printing processing is performed using the front recording head 22A. Details of the printing process will be described later.

  On the other hand, when the determination in step 102 is affirmative, that is, double-sided printing is requested, the process proceeds to step 112, and printing processing is performed using the front recording head 22A and the back recording head 22B. The details of the printing process will be described later as well.

  If the determination at step 106 is negative, that is, if there is no face instruction, the routine proceeds to step 114.

  In step 114, the recording head management table 42 is read into the controller 30, and the process proceeds to step 116, where it is determined whether or not the usage amount of the front recording head 22A is larger from the read recording head management table 42. . If the determination is negative, the process proceeds to step 110 described above, and if the determination is affirmative, the process proceeds to step 118.

  In step 118, a printing process is performed using the back recording head 22B. The details of the printing process will be described later in the same manner as the above-described printing process.

  If the determination in step 104 is negative, that is, if either of the recording heads 22A and 22B is unusable (for example, out of ink or failure), the process proceeds to step 120.

  In step 120, it is determined whether or not the front recording head 22A can be used. If the determination is affirmative, the process proceeds to step 112 described above, and printing processing is performed using the front recording head 22A. Is called. If the determination in step 120 is negative, the process proceeds to step 122 to determine whether the back recording head 22B can be used. If the determination is affirmative, the process proceeds to step 118 described above. Then, the printing process is performed using the back recording head 22B. That is, when either the front recording head 22A or the back recording head 22B is usable, printing is performed using the usable recording head, and thus either recording head 22A, 22B is not used. Even if it is possible, in the case of single-sided printing, printing using a usable recording head is possible.

  On the other hand, if the determination in step 122 is negative, that is, if neither of the recording heads 22A and 22B is usable, the process proceeds to step 124 to perform error processing indicating that printing is impossible, and a series of steps are performed. Terminate the process. In the error processing, for example, when the inkjet image forming apparatus 10 has a display unit, information indicating that printing is impossible (for example, information such as out of ink or failure) may be notified. Alternatively, the user may be notified by transmitting the information (for example, information such as out of ink or failure) to an external computer or the like that has requested printing.

  When each printing process is performed in steps 110, 112, and 118, the process proceeds to step 126, and the controller 30 determines whether or not printing is finished. This determination is made, for example, by determining whether or not printing has been completed for all print data of the print request. If the determination is negative, the process returns to step 102 described above and the determination of step 126 is performed. The above process is repeated until affirmative.

  Here, each printing process described above will be described. FIG. 5 is a flowchart showing the flow of each printing process. The printing process using the front recording head 22A, the printing process using the back recording head 22B, and the printing process using the front recording head 22A and the back recording head 22B are respectively used for printing. Since only the recording heads 22A and 22B are different, the printing process using the front recording head 22A will be described as a representative.

  When there is no print instruction from the controller 30, the inkjet image forming apparatus 10 is stopped in a standby state. That is, each head recovery means 16 is held in close contact with each head in order to prevent ink deterioration and head clogging.

  First, when the printing process is started, in step 200, each head recovery means 16 is lowered by the controller 30, and each print recording means 12 and each head recovery means 16 are separated so that the paper can be conveyed. At this time, the operation of a dummy jet or the like may be performed as necessary before printing.

  Subsequently, in step 202, the paper transport belt 20 is operated. That is, the drive of the drive motor 24 is controlled by the controller 30 via the motor driver 36, thereby driving the conveyor belt 20.

  Next, in step 204, it is determined whether or not the conveyance speed of the conveyance belt is stable. As described above, the determination is performed until the eccentricity control using the encoder or the like is performed and the conveyance speed is stabilized, and the process proceeds to step 206.

  In step 206, the paper 18 is sent out from a paper tray (not shown) that stores the paper, and the paper 18 is supplied to the transport belt 20.

  In step 208, the process waits until the leading edge of the paper 18 is detected by a sensor (various sensors 44) for detecting the leading edge of the paper provided on the most upstream side of the conveyor belt 20, and the process proceeds to step 210.

  In step 210, after a predetermined timing after detecting the leading edge of the paper, printing is sequentially performed on the paper 18 from the print recording means 12 corresponding to the uppermost front recording head 22A. That is, the controller 30 controls the print recording means 12 corresponding to the front recording head 22A via the head driver 34A to print an image. In the case of printing on the back recording head 22B, the print recording means 12 corresponding to the back recording head 22B is driven by the controller 30 via the head driver 34B to perform printing, and double-sided printing is performed. The print recording means 12 corresponding to the front recording head 22A and the back recording head 22B is driven by the controller 30 via the head drivers 34A and 34B to perform printing.

  In step 212, it is determined by the controller 30 whether or not the printing process for one sheet is completed, and the process waits until the determination is affirmed and the process proceeds to step 214.

  In step 214, when printing on one sheet of paper 18 is completed, it is determined whether or not to execute dummy jet according to the time from power-on, the cumulative number of printed sheets, the ink and the output amount, and the like. If the determination is affirmative, the process proceeds to step 216, a dummy jet is performed, and the series of printing processes is terminated. If the determination in step 214 is negative, that is, if the dummy jet is not performed, the series of printing processes is terminated.

  As described above, in the inkjet image forming apparatus 10 according to the embodiment of the present invention, when one of the recording heads 22A and 22B breaks down when performing single-sided printing, printing is performed using the other recording head. It can be carried out.

  Also, when the remaining amount of ink in one of the recording heads 22A and 22B is insufficient or has disappeared, printing can be performed using the other recording head.

  Also, if printing is always performed using one of the recording heads 22A and 22B, head wear and ink consumption will be biased, but the total amount of printed images and printed pages will be equalized. Since the use of the recording heads 22A and 22B is switched, the recording heads 22A and 22B can be used equally.

  Furthermore, since the face-up and face-down can be performed without using other means such as reversing the paper, the apparatus can be simplified.

  Therefore, the inkjet image forming apparatus 10 according to the embodiment of the present invention can obtain various effects that cannot be achieved by the single-sided printing configuration by using the recording heads 22A and 22B for printing on both sides.

  In the above-described embodiment, the inkjet image forming apparatus 10 to which the recording heads 22A and 22B configured to be divided into a plurality in the sheet width direction is described as an example. However, the present invention is not limited to this, and the front and back of the recording medium are used. As long as the configuration has at least two recording heads for printing, an image forming apparatus having another configuration may be applied.

1 is a perspective view illustrating a configuration of an inkjet image forming apparatus according to an embodiment of the present invention. It is a top view which shows the structure of the inkjet image forming apparatus concerning embodiment of this invention. 1 is a block diagram illustrating a configuration of a control system of an inkjet image forming apparatus according to an embodiment of the present invention. 4 is a flowchart showing a flow of printing control of the inkjet image forming apparatus according to the embodiment of the present invention. It is a flowchart which shows the flow of the printing process using a front recording head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Inkjet image forming apparatus 12 Print recording means 14 Print set 18 Paper 22A Front recording head 22B Back recording head 30 Controller 32 Operation panel 34A, 34B Head driver 38 Failure detection means 40 Ink remaining amount detection means 42 Recording head management table

Claims (10)

First recording means for recording an image on one surface of the recording medium;
Second recording means for recording an image on the other surface of the recording medium;
Switching means for switching driving to at least one of the first recording means and the second recording means for recording an image on a recording medium;
Control means for controlling the drive switching by the switching means based on the state of the first recording means and the second recording means when recording an image on one side of the recording medium;
An image forming apparatus.   The apparatus further comprises detection means for detecting the state of the first recording means and the second recording means, and the control means controls the drive switching by the switching means based on a detection result of the detection means. The image forming apparatus according to claim 1.   The image forming apparatus according to claim 2, wherein the detection unit detects whether the first recording unit and the second recording unit are usable as the state.   The image forming apparatus according to claim 3, wherein the detection unit detects a failure of the first recording unit and the second recording unit as the availability.   The image forming apparatus according to claim 3, wherein the detection unit detects, as the availability, the remaining amount of ink for the first recording unit and the second recording unit to record an image.   The image forming apparatus according to claim 2, wherein the detection unit detects the usage frequency of the first recording unit and the second recording unit as the state.   The said control means controls the said drive switching by the said switching means so that the usage frequency of the said 1st recording means and the said 2nd recording means detected by the said detection means may become equal. 6. The image forming apparatus according to 6.   The control means controls the drive switching by the switching means in accordance with the ink remaining amount of the first recording means or the second recording means detected by the detecting means. The image forming apparatus described in 1.   Input means for inputting the states of the first recording means and the second recording means, and the control means further controls the drive switching by the switching means in response to an input of the input means. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.   The apparatus further comprises instruction means for instructing the front and back of a recording medium for recording an image, and the control means further controls the drive switching by the switching means in accordance with an instruction from the instruction means. The image forming apparatus according to claim 1.

Images