Image forming apparatus

Abstract

To provide an image forming apparatus that is less likely to experience a situation where the liquid in the drain reservoir reaches its limit, significantly reducing user convenience. [Solution] Each time a maintenance operation (S2) is performed and ink from the print head is discharged into the waste ink box, an evaluation value is added to the memory installed in the waste ink box (S3). When it is determined that this evaluation value has reached a first threshold (S4, Yes), the control unit turns on special flushing if the user has permitted special flushing (S6, Yes) (S7). If the user has not permitted special flushing (S6, No), the control unit waits for the waste ink box to be replaced (S10) and then turns off the special flushing mode.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus.

Background Art

[0002] Conventionally, there is an image forming apparatus that forms an image on a medium by discharging a liquid from a discharge head onto the medium. In such an image forming apparatus, in order to recover the discharge performance of the liquid by the discharge head, the liquid is discharged from the discharge head. The liquid discharged from the discharge head is stored in a drainage storage unit. In such a drainage storage unit, if more liquid is added after the amount of the liquid reaches the limit, there is a risk that the liquid will overflow from the drainage storage unit. To avoid this, when the amount of the liquid reaches the limit or approaches the limit, the discharge of the liquid from the discharge head is not performed until the drainage storage unit is replaced.

[0003] Patent Document 1 is an example of such an image forming apparatus, and the ink (liquid) discharged from the head is stored in a waste liquid box (drainage storage unit). Then, when the amount of ink in the waste liquid box approaches the limit, in order to delay the amount of ink reaching the limit, a process of reducing the amount of ink discharged from the head is performed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] According to Patent Document 1, while it is possible to delay the ink level in the waste box reaching its limit, the ink level will eventually reach its limit. In that case, ink will not be discharged from the print head until the waste box is replaced. Therefore, the quality of image formation cannot be guaranteed, and image formation itself will be prohibited. This could significantly reduce user convenience.

[0006] The object of the present invention is to provide an image forming apparatus that is less likely to experience a situation where the liquid in the drain reservoir reaches its limit, significantly reducing user convenience. [Means for solving the problem]

[0007] The image forming apparatus according to the first invention comprises: an image forming unit having a discharge head for discharging liquid and discharging liquid from the discharge head onto a medium to form an image on the medium; a liquid discharge unit that performs a discharge operation to discharge liquid from the discharge head; a drained liquid storage unit that stores the liquid discharged from the discharge head by the liquid discharge unit; a liquid quantity acquisition unit that acquires the amount of liquid stored in the drained liquid storage unit; and a control unit, wherein the control unit performs an image forming process that causes the image forming unit to form an image based on image data; a liquid discharge process that, if the amount of liquid acquired by the liquid quantity acquisition unit has not reached a first threshold, causes the liquid discharge unit to perform a first discharge operation, which is the discharge operation in which the liquid is discharged from the discharge head and stored in the drained liquid storage unit; and a liquid discharge process that, if the amount of liquid acquired by the liquid quantity acquisition unit has reached the first threshold, causes the discharge unit to selectively perform a second discharge operation, which is the discharge operation in which the liquid is discharged from the discharge head onto a medium, and the first discharge operation.

[0008] The image forming apparatus according to the second invention comprises: an image forming unit having a discharge head for discharging liquid and discharging liquid from the discharge head onto a medium to form an image on the medium; a liquid discharge unit that performs a discharge operation to discharge liquid from the discharge head; a drained liquid storage unit that stores the liquid discharged from the discharge head by the liquid discharge unit; a liquid quantity acquisition unit that acquires the amount of liquid stored in the drained liquid storage unit; and a control unit, wherein the control unit performs an image forming process that causes the image forming unit to form an image based on image data; a liquid discharge process that, if the amount of liquid acquired by the liquid quantity acquisition unit has not reached a first threshold, causes the liquid discharge unit to perform a first discharge operation, which is the discharge operation in which the liquid is discharged from the discharge head and stored in the drained liquid storage unit; and if the amount of liquid acquired by the liquid quantity acquisition unit has reached the first threshold, causes the discharge unit to perform a second discharge operation, which is the discharge operation in which the liquid is discharged from the discharge head onto a medium. [Effects of the Invention]

[0009] The first discharge operation is performed until the amount of liquid in the drain reservoir reaches a threshold, at which point the second discharge operation becomes possible. This allows the discharge head to recover even if the amount of liquid in the drain reservoir becomes somewhat large, by performing the second discharge operation to discharge the liquid into the medium. Therefore, even if the first discharge operation cannot be performed immediately, it is less likely that it will be necessary to prohibit the image formation process itself in order to ensure the quality of image formation. Consequently, a device is realized that is less likely to experience a significant decrease in user convenience due to the liquid in the drain reservoir reaching its limit. [Brief explanation of the drawing]

[0010] [Figure 1] This is a block diagram showing the configuration of a printer according to a first embodiment, which is one embodiment of the present invention. [Figure 2] Figure 1 is a bottom view of the print head of the printer shown. [Figure 3] Figure 1 is a schematic diagram showing the relationship between the head position and the maintenance unit. [Figure 4]Figure 1 is a flowchart showing the processing flow executed by the printer's control unit. [Figure 5] This is the image displayed on the touch panel display during the process shown in Figure 4. [Figure 6] This is another image displayed on the touch panel display during the process shown in Figure 4. [Figure 7] This flowchart shows another processing flow performed by the printer's control unit in Figure 1. [Figure 8] This is a block diagram showing the configuration of a printer according to a second embodiment, which is another embodiment of the present invention. [Figure 9] Figure 8 is a flowchart showing the processing flow executed by the printer's control unit. [Modes for carrying out the invention]

[0011] [First Embodiment] A printer 1 according to the first embodiment, which is a preferred embodiment of the present invention, will be described below with reference to Figures 1 to 7.

[0012] As shown in Figure 1, the printer 1 (corresponding to the "image forming apparatus" of the present invention) has an image forming unit 10, a touch panel display 32, a maintenance unit 40, and a control unit 50.

[0013] The image forming unit 10 includes a paper storage unit 11 for storing printing paper, a paper supply unit 12 for supplying paper from the paper storage unit 11, an ink ejection head 13, an ink supply unit 14 for supplying ink to the head 13, and a head moving unit 15 for moving the head 13. Multiple nozzles 13a for ejecting ink are open on the lower surface of the head 13 (corresponding to the "ejection head" of this invention) (see Figure 2). Each nozzle 13a ejects either a single color ink or multiple color inks. The ink supply unit 14 supplies these inks to the head 13. The head moving unit 15 moves the head 13 between an image forming position where ink is ejected onto the paper supplied from the paper supply unit 12 and a maintenance position where it receives maintenance operations by the maintenance unit 40, as described later (see Figure 3). At the image forming position, the head 13 is driven by the control unit 50 and ejects ink onto the paper to form a color image or monochrome image indicated by the image data on the paper. Furthermore, the print head 13 is driven by the control unit 50 in the maintenance position described later, and ejects ink to the maintenance unit 40.

[0014] The touch panel display 32 (corresponding to the "input unit" and "notification unit" of the present invention) displays characters, images, etc. on the screen. The touch panel display 32 also detects the contact position when a finger or the like touches the screen and outputs the detection result to the control unit 50. As a result, the touch panel display 32 can accept various user inputs, such as user permission, as described later.

[0015] The maintenance unit 40 is installed in the printer 1 to perform a maintenance operation on the head 13 at the maintenance position shown in FIG. 3. The maintenance operation is performed to recover the ejection performance of the head 13. There are two types of maintenance operations according to this embodiment, namely a purge operation and a flushing operation. The maintenance unit 40 includes a cap 41 that covers a part of the lower surface of the head 13, a lifting and lowering unit 42 that raises and lowers the cap 41, and a waste liquid box 44 (corresponding to the "drainage storage unit" of the present invention) connected to the lifting and lowering unit 42 through a pump 43. The cap 41 is disposed below the maintenance position. When the lifting and lowering unit 42 raises the cap 41 toward the head 13 at the maintenance position, the upper end of the cap 41 comes into close contact with the lower surface of the head 13. Thereby, the cap 41 covers the region (the region of the two-dot chain line in FIG. 2) where the nozzles 13a open on the lower surface of the head 13 in plan view. An air passage connected to the pump 43 is formed in the lifting and lowering unit 42. An opening 42a (see FIG. 2) of this passage opens on the upper surface of the lifting and lowering unit 42. The waste liquid box 44 stores the ink discharged from the head 13. The waste liquid box 44 is detachably installed in the printer 1.

[0016] The purge operation (corresponding to an example of the "first discharge operation" of the present invention) is performed as follows. When the pump 43 operates with the cap 41 in close contact with the lower surface of the head 13, the space in the cap 41 is sucked by the pump 43 through the air passage and the opening 四十二 a in the lifting and lowering unit 42. As a result, the ink in the head 13 is discharged from the nozzles 13a into the space in the cap 41, and further discharged from the opening 42a through the passage in the lifting and lowering unit 42 and the pump 43 into the waste liquid box 44.

[0017] The flushing operation (which corresponds to another example of the "first discharge operation" of the present invention) is performed as follows. With the cap 41 below the head 13, the head 13 is driven to discharge liquid. The ink from the head 13 is discharged into the cap 41. The ink discharged into the cap 41 is sucked by the pump 43 from the opening 42a and discharged to the waste liquid box 44 through the passage in the lifting part 42 and the pump 43. The amount of ink discharged to the waste liquid box 44 in one flushing operation is smaller than the amount of ink discharged to the waste liquid box 44 in one purge operation.

[0018] Note that the function of the head 13 and the maintenance unit 40 performing the maintenance operation corresponds to the function of the "liquid discharge unit" of the present invention performing the "first discharge operation".

[0019] A memory 44M is installed in the waste liquid box 44. When the waste liquid box 44 is arranged at an appropriate position in the printer 1, the contacts on the memory 44M side and the contacts on the printer 1 side are connected, so that the control unit 50 can read and write the stored content of the memory 44M. The memory 44M stores an evaluation value representing the amount of ink stored in the waste liquid box 44.

[0020] The control unit 50 includes hardware such as a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an ASIC (Application Specific Integrated Circuit). The ROM stores program data and the like executed by the CPU and the ASIC. The RAM stores image data acquired from an external PC or the like, or data used when the CPU executes a program. The CPU, which is hardware, executes various processes such as processes for controlling the operations of the image forming unit 10, the touch panel display 32, and the maintenance unit 40 according to the program data and other data, which are software stored in the ROM and the RAM.

[0021] In this embodiment, the control unit 50 performs image forming and maintenance processing. Image forming processing is the process of controlling the image forming unit 10 to form an image on the paper indicated by image data transmitted from a PC or other device owned by the user or acquired from a storage medium. Maintenance processing is the process of moving the head 13 to the maintenance position using the head moving unit 15, and causing the head 13 and the maintenance unit 40 to perform a purge operation or a flushing operation as maintenance. Maintenance operations may be performed periodically, or each time the ink ejection operation related to image formation by the head 13 reaches a predetermined number of times. It may also be performed when an ejection failure is detected in the head 13.

[0022] The control unit 50 adds a predetermined value (>0) to the memory 44M each time ink is discharged from the head 13 during maintenance. Based on whether the evaluation value stored in the memory 44M has reached the predetermined value, the control unit 50 obtains the amount of ink in the waste ink box 44.

[0023] Conventionally, when the amount of ink in the waste ink box 44 reaches its limit, the control unit 50 does not perform either image forming or maintenance processing until the waste ink box 44 is replaced. Maintenance processing is not performed because if ink is discharged from the head 13 when the waste ink box 44 is full, the ink will overflow from the waste ink box 44. Image forming processing is not performed because if maintenance processing is not performed, and the ejection performance of the head 13 deteriorates, performing image forming processing without restoring the ejection performance will result in a decrease in the quality of the image formed on the paper. However, if image forming processing is not performed, user convenience is significantly reduced.

[0024] Therefore, in order to avoid the above-mentioned situation where the amount of ink in the waste liquid box 44 reaches its limit and user convenience is reduced, this embodiment has a configuration that performs maintenance processing and image forming processing as follows.

[0025] Figure 4 shows the details of the maintenance process performed by the control unit 50. First, the control unit 50 determines whether the special flushing mode is on or off (S1). Special flushing will be described later. If the control unit 50 determines that the special flushing mode is on (S1, Yes), it proceeds to process S5. If it determines that the special flushing mode is not on (S1, No), it proceeds to process S2.

[0026] In S2, the control unit 50 moves the head 13 to the maintenance position using the head moving unit 15, and also causes the head 13 and the maintenance unit 40 to perform a purge or flushing operation as a maintenance operation. Next, the control unit 50 adds a predetermined value to the evaluation value of the memory 44M of the waste ink box 44 (S3). Next, the control unit 50 determines whether the evaluation value of the memory 44M has reached a first threshold (S4). Here, the first threshold is set to a value that corresponds to an amount slightly smaller than the limit of the ink amount in the waste ink box 44. More specifically, it is set to a value such that even if one more purge operation is performed, the amount of ink in the waste ink box 44 will not reach the limit. This is because if the first threshold is too close to the limit, the purge operation will be performed because the amount of ink in the waste ink box 44 is close to the limit but has not exceeded the first threshold, which may cause ink to overflow from the waste ink box 44.

[0027] In S4, if the control unit 50 determines that the evaluation value of memory 44M has not reached the first threshold (S4, No), it terminates the series of processes. If the control unit 50 determines that the evaluation value of memory 44M has reached the first threshold (S4, Yes), it displays the first message M1 and image R1 shown in Figure 5 on the touch panel display 32 (S5). The first message M1 contains the string "Do you want to perform special flashing?". Special flashing is the process in S7 described later. Next, the control unit 50 allows the touch panel display 32 to accept user input based on image R1 in Figure 5 (S6; corresponding to the "permission input process" of the present invention). Image R1 contains the strings "Yes" and "No", and by touching the user's finger or the like to either of these display positions, the user input is made to select whether or not to permit special flashing.

[0028] If "Yes" is selected, meaning that the user has authorized special flushing (S6, Yes), the control unit 50 causes the head 13 to perform special flushing and turns on the special flushing mode (S7). Special flushing is an operation that replaces the flushing operation, in which the head 13 ejects ink onto the paper supplied from the paper supply unit 12. Note that the paper used for special flushing in this way will be discarded. For this reason, the user should place any paper that can be used for special flushing into the paper storage unit 11 before entering "Yes" in the S6 process. After the S7 process is completed, the series of processes ends. Since the special flushing mode is turned on in S7, in subsequent maintenance processes, the process from S5 will be executed according to the conditional branch in S1.

[0029] The function of head 13 to perform special flushing corresponds to the function of the "liquid discharge unit" of the present invention to perform the "second discharge operation".

[0030] If "No" is selected in S6, meaning that special flushing is not permitted to the user (S6, No), the control unit 50 displays the second message M2 and image R2 shown in Figure 6 on the touch panel display 32 (S8). The second message M2 contains the string "Do you want to replace the waste liquid box?" (corresponding to the "information prompting replacement of the drain liquid storage unit" in the present invention). Next, the control unit 50 allows the touch panel display 32 to accept user input based on image R2 in Figure 6 (S9; corresponding to the "replacement yes / no input process" in the present invention). Image R2 contains the strings "Yes" and "No", and by touching either of these display positions with the user's finger, user input is made to select whether or not to replace the waste liquid box 44.

[0031] If "No" is selected, meaning the user has chosen not to replace the waste liquid box 44 (S9, No), the control unit 50 returns to the process in S5. As a result, if user permission is obtained in S6, the special flushing in S7 is executed. If "Yes" is selected in S9, meaning the user has chosen to replace the waste liquid box 44 (S9, Yes), the control unit 50 waits until the replacement of the waste liquid box 44 is actually performed (S10, No). In this process, the control unit 50 acquires the replacement status of the waste liquid box 44 based on whether or not the memory 44M has become readable and writeable. For example, if the used waste liquid box 44 is removed from the printer 1, making the memory 44M temporarily unreadable and writeable, and then a new waste liquid box 44 is installed in the printer 1, making the memory 44M readable and writeable again, this indicates that the waste liquid box 44 has been replaced. The function of the control unit 50 in acquiring the replacement status of the waste liquid box 44 in this way corresponds to the function of the "replacement status acquisition unit" of the present invention. The replacement status of the waste liquid box 44 may be obtained not based on whether or not reading and writing to the memory 44M becomes possible, but by directly detecting the attachment or detachment of the waste liquid box 44 using an optical sensor or the like.

[0032] When the control unit 50 determines that the waste liquid box 44 has been replaced (S10, Yes), the control unit 50 switches the special flushing mode to off (S11). Then, the series of processes ends. Since the special flushing mode is turned off in S11, the maintenance operation in S2 will be executed in the next maintenance process due to the conditional branch in S1. Thus, the process in which the second message M2 is displayed in S8, the waste liquid box 44 is replaced in S10, and the maintenance operation in S2 is executed in the next maintenance process corresponds to the "discharge process after notification" and the "discharge process after replacement" of the present invention.

[0033] Through the process shown in Figure 4, it is determined in S4 whether the evaluation value has reached the first threshold. As a result, special flushing in S7 is performed, or after replacing the waste liquid box 44 in S10, the maintenance operation in S2 is executed in the next maintenance process. This corresponds to the "liquid discharge process" of the present invention.

[0034] Figure 7 shows the sequence of operations from when the control unit 50 acquires image data to when it executes the image formation process. First, when image data is acquired (S21), the control unit 50 determines whether the evaluation value in memory 44M has reached the second threshold (S22). Here, the second threshold is set to a value smaller than the first threshold. If it is determined that the evaluation value has not reached the second threshold (S22, No), the control unit 50 executes the image formation process based on the image data acquired in S21 (S30). If it is determined that the evaluation value has reached the second threshold (S22, Yes), the control unit 50 executes the processes in S23 to S29, and then executes the image formation process based on the image data acquired in S21 (S30). Here, the processes in S23 to S29 are the same as the processes in S5 to S11 in Figure 4.

[0035] According to the embodiment described above, a purge operation and a flushing operation are performed as maintenance operations until the amount of ink in the waste liquid box 44 reaches a first threshold, and when the amount of ink in the waste liquid box 44 reaches the first threshold, a special flushing operation becomes possible. As a result, even if the amount of ink in the waste liquid box 44 becomes somewhat large, the state of the head 13 can be restored by performing a special flushing operation to discharge the ink onto the paper. Therefore, even if maintenance operations cannot be performed immediately, it is less likely that it will be necessary to prohibit the execution of image formation itself in order to ensure the quality of image formation on the paper. Thus, a device is realized in which the situation in which user convenience is greatly reduced due to the ink in the waste liquid box 44 reaching its limit is less likely to occur.

[0036] Furthermore, in this embodiment, user input is received based on the first message M1 and image R1 shown in Figure 5 on the touch panel display 32, and special flashing is performed in response to permission from the user. Therefore, it is less likely that special flashing will be performed against the user's intention.

[0037] Furthermore, in this embodiment, if the user does not permit the execution of special flushing, the second message M2 shown in Figure 6 is displayed on the touch panel display 32. The second message M2 represents information prompting the replacement of the waste liquid box 44. This ensures that the replacement of the waste liquid box 44 is appropriately prompted.

[0038] Furthermore, in this embodiment, a second message M2 prompting the replacement of the waste liquid box 44 is displayed on the touch panel display 32 at S8 in Figure 4. After the replacement of the waste liquid box 44 is confirmed at S10, the maintenance operation at S2 is executed in the next maintenance process. This ensures that the maintenance operation is performed at the appropriate time.

[0039] Furthermore, in this embodiment, at S8 in Figure 4, the second message M2 in Figure 6 is displayed on the touch panel display 32, prompting the user to replace the waste liquid box 44. Then, at S9, the user is asked whether or not to replace it. Depending on the result of this inquiry, the next maintenance process may involve either the maintenance operation in S2 or the special flushing in S7. This makes it less likely that processing will be performed against the user's intentions.

[0040] Furthermore, in this embodiment, if a request arises to restore the ejection performance of the ejection head during the execution of the image forming process, it is difficult to perform special flushing in parallel with the image forming on the paper. Therefore, neither maintenance operation nor special flushing can be performed, which may result in low-quality image formation or make image formation itself impossible. In contrast, according to this embodiment, when image data is acquired, if the evaluation value of memory 44M has reached the second threshold, that is, if the amount of ink in the waste liquid box 44 is sufficient, special flushing and maintenance operation are selectively performed before the image forming process is executed. As a result, the risk of a request arising to restore the ejection performance of the head 13 during the subsequent image forming process is reduced. This makes it less likely that low-quality image formation will occur or that image formation itself will become impossible.

[0041] Furthermore, in this embodiment, the second threshold is set to a smaller value than the first threshold. As a result, when it is determined that the amount of ink in the waste liquid box 44 has reached the second threshold, even if there is still some leeway in the ink in the waste liquid box 44 compared to when the amount of ink in the waste liquid box 44 has reached the first threshold, special flushing or replacement of the waste liquid box 44 will be performed to reduce the risk of the waste liquid box 44 reaching its limit. Note that the second threshold may also be the same value as the first threshold.

[0042] Furthermore, in this embodiment, the control unit 50 increases the evaluation value in the memory 44M each time a maintenance operation is performed. As a result, the evaluation value appropriately reflects the amount of ink in the waste liquid box 44.

[0043] [Second Embodiment] Hereinafter, a printer 101 according to a second embodiment, which is another embodiment of the present invention, will be described with reference to Figures 8 and 9. The configuration of printer 101 has many similarities with the configuration of printer 1 according to the first embodiment. For this reason, the same reference numerals as in the first embodiment will be used for such common components, and their descriptions will be omitted as appropriate.

[0044] The difference between printer 101 and printer 1 is that printer 101 uses a control unit 150 instead of a control unit 50. Furthermore, the difference between printer 101 and printer 50 is that printer 150 performs the following processing shown in Figure 9 instead of the processing shown in Figure 4.

[0045] The control unit 150 determines whether the special flashing mode is on or off (S41). If the control unit 150 determines that the special flashing mode is on (S41, Yes), it proceeds to process S45. If it determines that the special flashing mode is not on (S41, No), it proceeds to process S42.

[0046] In S42, the control unit 150 moves the head 13 to the maintenance position using the head moving unit 15, and also causes the head 13 and the maintenance unit 40 to perform a purge operation or a flushing operation as a maintenance operation. Next, the control unit 150 adds a predetermined value to the evaluation value of the memory 44M of the waste liquid box 44 (S43). Next, the control unit 150 determines whether the evaluation value of the memory 44M has reached a first threshold (same as in the first embodiment) (S44).

[0047] In S44, if it is determined that the evaluation value of memory 44M has not reached the first threshold (S44, No), the control unit 150 terminates the series of processes. If it is determined that the evaluation value of memory 44M has reached the first threshold (S44, Yes), the control unit 150 waits until the paper for special flushing is ready (S45). This process is performed, for example, by waiting until the optical sensor detects that the user has reinserted paper into the paper storage unit 11, or by waiting until user input is received via the touch panel display 32 indicating that the paper is ready.

[0048] Next, the control unit 150 causes the head 13 to perform special flushing and turns on the special flushing mode (S46). Then, the series of processes is completed. Since the special flushing mode is turned on in S46, in subsequent maintenance processes, the process from S45 will be executed according to the conditional branch in S41. The special flushing mode is switched off by the control unit 150 when the replacement of the waste liquid box 44 is detected.

[0049] The function of head 13 to perform special flushing corresponds to the function of the "liquid discharge unit" of the present invention to perform the "second discharge operation".

[0050] According to the embodiment described above, a purge operation and a flushing operation are performed as maintenance operations until the amount of ink in the waste liquid box 44 reaches a first threshold, and when the amount of ink in the waste liquid box 44 reaches the first threshold, special flushing becomes possible. Then, special flushing is performed at S46 in Figure 9. As a result, even if the amount of ink in the waste liquid box 44 becomes somewhat large, the state of the head 13 can be restored. Therefore, even if maintenance operations cannot be performed immediately, it is less likely that it will be necessary to prohibit the execution of image formation itself in order to ensure the quality of image formation on the paper. Thus, a device is realized in which the situation in which user convenience is greatly reduced due to the ink in the waste liquid box 44 reaching its limit is less likely to occur.

[0051] <Variation> Although embodiments of the present invention have been described above with reference to the drawings, it should be understood that the specific configurations are not limited to these embodiments. The scope of the present invention is indicated by the claims rather than the above description of embodiments, and all modifications within the meaning and scope equivalent to the claims are included.

[0052] For example, in the embodiment described above, at S6 in Figure 4, either user input that permits special flushing or user input that disperforms special flushing is received. Alternatively, even if there is no direct user input that disperforms special flushing, if no user input permitting special flushing is given for a certain period of time or longer, it may be treated as if special flushing was not permitted to the user.

[0053] Furthermore, in the above-described embodiment, user input indicating permission for special flushing is received at S6 in Figure 4 after the maintenance process has started. Alternatively, user input indicating whether or not to permit special flushing may be received in advance before the maintenance process begins.

[0054] In addition, although the embodiments described above have described the application of the present invention to printer 1, the invention is not limited thereto. The present invention may also be applied to other inkjet-type image forming devices that eject ink from a head, such as multifunction printers and copiers, or systems having such image forming devices. [Explanation of symbols]

[0055] 1. Printer 10 Image forming unit 13 heads 32 Touch panel display 40 Maintenance Department 44 Waste liquid box 50 Control Unit M1 First Message M2 Second Message

Claims

1. An image forming unit having a discharge head for discharging liquid, and discharging liquid from the discharge head onto a medium to form an image on the medium, A liquid discharge unit that performs a discharge operation to discharge liquid from the discharge head, The liquid discharge section includes a drainage storage section that stores the liquid discharged from the discharge head, A liquid quantity acquisition unit that acquires the amount of liquid stored in the drainage storage unit, It includes a control unit, The control unit, Image forming process that causes the image forming unit to form an image based on image data, An image forming apparatus characterized by performing a liquid discharge process in which, if the amount of liquid acquired by the liquid amount acquisition unit has not reached a first threshold, the liquid discharge unit is instructed to perform a first discharge operation, which is a discharge operation in which the liquid is discharged from the discharge head and stored in the drained liquid storage unit, and if the amount of liquid acquired by the liquid amount acquisition unit has reached the first threshold, the discharge unit is instructed to selectively perform a second discharge operation, which is a discharge operation in which the liquid is discharged from the discharge head into a medium, and the first discharge operation.

2. An image forming unit having a discharge head for discharging liquid, and discharging liquid from the discharge head onto a medium to form an image on the medium, A liquid discharge unit that performs a discharge operation to discharge liquid from the discharge head, The liquid discharge section includes a drainage storage section that stores the liquid discharged from the discharge head, A liquid quantity acquisition unit that acquires the amount of liquid stored in the drainage storage unit, It includes a control unit, The control unit, Image forming process that causes the image forming unit to form an image based on image data, An image forming apparatus characterized by performing a liquid discharge process, in which, if the amount of liquid acquired by the liquid amount acquisition unit has not reached a first threshold, the liquid discharge unit is instructed to perform a first discharge operation, which is a discharge operation in which the liquid is discharged from the discharge head and stored in the drained liquid storage unit, and if the amount of liquid acquired by the liquid amount acquisition unit has reached the first threshold, the discharge unit is instructed to perform a second discharge operation, which is a discharge operation in which the liquid is discharged from the discharge head into a medium.

3. It also includes an input section that accepts user input, The control unit, A permission input process is executed to cause the input unit to receive user input indicating whether or not to permit the second discharge operation. The image forming apparatus according to claim 1, characterized in that when the permission input process receives the user input indicating permission to perform the second discharge operation, the liquid discharge unit is instructed to perform the second discharge operation in the liquid discharge process.

4. It also has a broadcasting department to disseminate information, The control unit, The image forming apparatus according to claim 3, characterized in that when the permission input processing receives the user input indicating that the second discharge operation is not permitted, the notification unit is instructed to provide information prompting the replacement of the drainage reservoir.

5. The system further includes a replacement status acquisition unit that acquires the replacement status of the drainage storage unit, The control unit, After the notification unit is notified of information prompting the replacement of the drainage reservoir, the post-notification discharge process, which is the liquid discharge process performed after notification, is executed. The aforementioned post-notification discharge process is as follows: The image forming apparatus according to claim 4, characterized in that it includes a post-replacement discharge process in which the liquid discharge unit performs the first discharge operation when the replacement status acquired by the replacement status acquisition unit indicates that the drainage storage unit has been replaced.

6. The control unit, After the notification unit is notified of information prompting the replacement of the drainage storage unit, the replacement / replacement input process is further executed, which causes the input unit to receive user input indicating whether or not to replace the drainage storage unit. In the aforementioned post-notification discharge process, The image forming apparatus according to claim 5, characterized in that when the replacement / replacement input process receives a user input indicating that the drainage reservoir should be replaced, the post-replacement discharge process is executed, and when the replacement / replacement input process receives a user input indicating that the drainage reservoir should not be replaced, and the permission input process receives a user input permitting the second discharge operation, the liquid discharge unit is made to perform the second discharge operation.

7. The control unit, The image forming apparatus according to claim 1 or 2, characterized in that when the image data is received from an external source, if the amount of liquid acquired by the liquid amount acquisition unit reaches a second threshold, the liquid discharge unit is instructed to perform the second discharge operation, or to selectively perform the first discharge operation and the second discharge operation, and thereafter the image forming process based on the image data is started, and if the amount of liquid acquired by the liquid amount acquisition unit does not reach a second threshold, the image forming process is started without having the liquid discharge unit perform either the first discharge operation or the second discharge operation.

8. The image forming apparatus according to claim 7, characterized in that the second threshold is smaller than the first threshold.

9. The system further includes a liquid quantity storage unit that stores an evaluation value related to the amount of the liquid. The image forming apparatus according to claim 1 or 2, characterized in that the liquid volume acquisition unit increases the evaluation value each time the liquid discharge unit performs the first discharge operation.

Images