Image forming device and setting method

Abstract

To provide an image forming apparatus and setting method capable of suppressing the drive voltage, which is set based on the ink temperature, from exceeding the output range of the power supply. [Solution] The image forming apparatus includes a first power supply 42 that outputs a drive voltage V1 within an output range corresponding to the input voltage V2 in response to the input of an input voltage V2; a first setting processing unit that sets the drive voltage V1 based on the detection result of the ink temperature; an acquisition processing unit that acquires the upper and lower limits of the settable range of the drive voltage V1 by the first setting processing unit; and a second setting processing unit that sets the input voltage V2 if either of the acquired upper or lower limits is not included in the output range.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus and a setting method.

Background Art

[0002] An image forming apparatus including a discharge unit that discharges ink from a nozzle in response to an input of a drive voltage is known (for example, see Patent Document 1).

[0003] Also, an image forming apparatus that adjusts the drive voltage based on the temperature of the ink during execution of an image forming process for forming an image on a sheet is known. For example, this type of image forming apparatus includes a power supply, a detection processing unit, and a setting processing unit. The power supply outputs the drive voltage within an output possible range corresponding to the input voltage to the discharge unit in response to an input of the input voltage. The detection processing unit detects the temperature of the ink during execution of the image forming process. The setting processing unit sets the drive voltage based on a detection result by the detection processing unit. The settable range of the drive voltage by the setting processing unit is appropriately set according to a change in the ink discharge performance of the discharge unit due to aging deterioration of a recording head including the discharge unit.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the image forming apparatus, the upper or lower limit of the configurable range after a setting change may exceed or fall below the output range. In this case, if the setting processing unit sets a drive voltage that exceeds or falls below the output range, the image forming process may stop due to an error, or the drive voltage of the upper or lower limit of the output range may be output instead of the set drive voltage, resulting in a decrease in the quality of the image formed by the image forming process.

[0006] The object of the present invention is to provide an image forming apparatus and a setting method that can suppress the drive voltage, which is set based on the ink temperature, from exceeding the output range of the power supply. [Means for solving the problem]

[0007] An image forming apparatus according to one aspect of the present invention comprises a discharge unit, a first power supply, a detection processing unit, a first setting processing unit, a second setting processing unit, an acquisition processing unit, and a third setting processing unit. The discharge unit discharges ink from a nozzle in response to a preset drive voltage input. The first power supply outputs the drive voltage to the discharge unit within an output range corresponding to a preset input voltage. The detection processing unit detects the temperature of the ink during the execution of an image forming process in which an image is formed on a sheet using the discharge unit. The first setting processing unit sets the drive voltage based on the detection result by the detection processing unit. The second setting processing unit sets the configurable range of the drive voltage by the first setting processing unit in accordance with a predetermined setting operation. The acquisition processing unit acquires the upper and lower limits of the configurable range at a specific timing outside the execution period of the image forming process. The third setting processing unit sets the input voltage based on the upper and lower limits if either the upper or lower limit acquired by the acquisition processing unit is not included in the output range.

[0008] A setting method according to another aspect of the present invention is performed in an image forming apparatus comprising: a discharge unit that discharges ink from a nozzle in response to a preset drive voltage input; and a first power supply that outputs the drive voltage within an output range corresponding to the input voltage to the discharge unit in response to a preset input voltage input, and includes a detection step, a first setting step, a second setting step, an acquisition step, and a third setting step. In the detection step, the temperature of the ink is detected during the execution of an image forming process in which an image is formed on a sheet using the discharge unit. In the first setting step, the drive voltage is set based on the detection result of the detection step. In the second setting step, the settable range of the drive voltage by the first setting step is set according to a predetermined setting operation. In the acquisition step, the upper and lower limits of the settable range are acquired at a specific timing outside the execution period of the image forming process. In the third setting step, if either the upper or lower limit acquired by the acquisition step is not included in the output range, the input voltage is set based on the upper and lower limits. [Effects of the Invention]

[0009] According to the present invention, it is possible to suppress the drive voltage, which is set based on the ink temperature, from exceeding the output range of the power supply. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a block diagram showing the system configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2] Figure 2 shows the configuration of the image forming section of an image forming apparatus according to an embodiment of the present invention. [Figure 3] Figure 3 shows the configuration of the recording head of an image forming apparatus according to an embodiment of the present invention. [Figure 4] Figure 4 shows an example of the output range of the first power supply in an image forming apparatus according to an embodiment of the present invention. [Figure 5]Figure 5 is a flowchart showing an example of a drive voltage setting process performed in an image forming apparatus according to an embodiment of the present invention. [Figure 6] Figure 6 is a flowchart showing an example of the input voltage setting process performed in an image forming apparatus according to an embodiment of the present invention. [Modes for carrying out the invention]

[0011] The embodiments of the present invention will be described below with reference to the attached drawings. Note that the following embodiments are merely examples of the present invention and do not limit the technical scope of the present invention.

[0012] [Configuration of the image forming apparatus 100] First, with reference to Figure 1, the configuration of the image forming apparatus 100 according to an embodiment of the present invention will be described.

[0013] The image forming apparatus 100 is a printer capable of forming images on a sheet using an inkjet method. The image forming apparatus 100 is a so-called line-print type image forming apparatus. The present invention is applicable to image forming apparatuses such as printers, fax machines, copiers, and multifunction devices that are capable of forming images on a medium such as a sheet using an inkjet method.

[0014] As shown in Figure 1, the image forming apparatus 100 comprises a sheet transport unit 1, an image forming unit 2, an operation display unit 3, a communication unit 4, a storage unit 5, and a control unit 6.

[0015] The sheet transport unit 1 transports the sheets on which images are formed by the image forming unit 2. The sheet transport unit 1 includes a paper feed cassette and a plurality of transport rollers.

[0016] The image forming unit 2 forms an ink image on the sheet being transported by the sheet transport unit 1.

[0017] The operation display unit 3 is the user interface of the image forming apparatus 100. The operation display unit 3 includes a display unit and an operation unit. The display unit displays various kinds of information according to a control instruction from the control unit 6. For example, the display unit is a liquid crystal display. The operation unit inputs various kinds of information to the control unit 6 according to a user's operation. For example, the operation unit is a touch panel.

[0018] The communication unit 4 is a communication interface that executes wired or wireless data communication with an external information processing apparatus such as a personal computer.

[0019] The storage unit 5 is a non-volatile storage device. For example, the storage unit 5 is a non-volatile memory such as a flash memory, a storage device such as a solid state drive (SSD), and a hard disk drive (HDD).

[0020] The control unit 6 comprehensively controls the image forming apparatus 100. As shown in FIG. 1, the control unit 6 includes a CPU 11, a ROM 12, and a RAM 13. The CPU 11 is a processor that executes various arithmetic processes. The ROM 12 is a non-volatile storage device in which information such as a control program for causing the CPU 11 to execute various processes is stored in advance. The RAM 13 is a volatile or non-volatile storage device used as a temporary storage memory (working area) for various processes executed by the CPU 11. The CPU 11 comprehensively controls the image forming apparatus 100 by executing various control programs stored in advance in the ROM 12. Note that the control unit 6 may be constituted by an electronic circuit such as an integrated circuit (ASIC).

[0021] [Configuration of the image forming unit 2] Next, the configuration of the image forming unit 2 will be described while referring to FIGS. 2 and 3. Here, FIG. 2 is a view of a plurality of line heads 20 as seen from the nozzle surface 32 side. Further, FIG. 3 is a block diagram showing the configuration of the recording head 31. In FIG. 3, the recording head 31 is shown by a broken line. Also, in FIG. 3, a block 40 composed of a plurality of piezoelectric elements 41 is shown by a two-dot chain line.

[0022] The image forming unit 2 is equipped with four line heads 20 (21, 22, 23, 24) (see Figure 2) corresponding to four printing colors (black, cyan, magenta, and yellow).

[0023] The four line heads 20 form an ink image on the sheet being transported in the transport direction D1 (see Figure 2) by the sheet transport unit 1.

[0024] As shown in Figure 2, each line head 20 is elongated in the width direction D2 (see Figure 2), which is perpendicular to the conveying direction D1 (see Figure 2). The four line heads 20 are arranged at equal intervals along the conveying direction D1.

[0025] Of the four line heads 20, line head 21, located at the upstream end of the transport direction D1, corresponds to the black printing color. Of the four line heads 20, line head 22, located downstream of line head 21 in the transport direction D1 and adjacent to line head 21, corresponds to the cyan printing color. Of the four line heads 20, line head 23, located downstream of line head 22 in the transport direction D1 and adjacent to line head 22, corresponds to the magenta printing color. Of the four line heads 20, line head 24, located at the downstream end of the transport direction D1, corresponds to the yellow printing color.

[0026] Each line head 20 has a common configuration, except that it corresponds to a different printing color. Therefore, the following description will only cover the configuration of line head 21, and will omit the description of the configurations of the other line heads 20.

[0027] The line head 21 is equipped with three recording heads 31 (see Figure 2). Each recording head 31 has a common configuration. The number of recording heads 31 included in the line head 20 may be two or fewer, or four or more.

[0028] As shown in Figure 2, each recording head 31 has a rectangular nozzle surface 32 that is elongated in the width direction D2. Each recording head 31 is formed in a prismatic shape with the nozzle surface 32 as its base. The three recording heads 31 are arranged in a staggered pattern along the width direction D2.

[0029] As shown in Figure 2, the line head 21 includes a nozzle group 30 (see Figure 2) comprising a plurality of nozzles 33. The nozzle group 30 is composed of all the nozzles 33 provided on the line head 21. The plurality of nozzles 33 constituting the nozzle group 30 are arranged at equal intervals along the width direction D2.

[0030] Specifically, the multiple nozzles 33 constituting the nozzle group 30 are distributed and arranged across three nozzle surfaces 32. For example, each nozzle surface 32 is provided with a nozzle row formed by multiple nozzles 33 arranged at equal intervals along the width direction D2. The three recording heads 31 are arranged in a staggered pattern along the width direction D2 so that the multiple nozzles 33 constituting the nozzle group 30 are arranged at equal intervals along the width direction D2. Note that multiple nozzle rows may be arranged along the transport direction D1 on each nozzle surface 32.

[0031] As shown in Figure 3, the recording head 31 includes piezoelectric elements 41 corresponding to each nozzle 33 arranged on the nozzle surface 32. Also as shown in Figure 3, the recording head 31 includes a plurality of first power supplies 42, second power supplies 43, and a temperature sensor 44.

[0032] Each piezoelectric element 41 ejects ink from the nozzle 33 in response to a preset drive voltage V1 (see Figure 3). The piezoelectric element 41 is an example of the ejection unit of the present invention.

[0033] Each of the first power supplies 42 is provided in correspondence with a block 40 (see Figure 3) composed of multiple piezoelectric elements 41. In other words, the recording head 31 comprises multiple blocks 40 and multiple first power supplies 42 corresponding to the multiple blocks 40.

[0034] Each of the first power supplies 42 outputs a drive voltage V1 within the output range corresponding to the input voltage V2 (see Figure 3) to each of the piezoelectric elements 41 included in block 40, in response to a preset input voltage V2 (see Figure 3). For example, each of the first power supplies 42 is a linear regulator.

[0035] Here, Figure 4 shows the output range of the first power supply 42. As shown in Figure 4, when the input voltage V2 is 28V, the output range of the first power supply 42 is 22V to 26V. When the input voltage V2 is 27V, the output range of the first power supply 42 is 21V to 25V. When the input voltage V2 is 26V, the output range of the first power supply 42 is 20V to 24V. When the input voltage V2 is 25V, the output range of the first power supply 42 is 19V to 23V. When the input voltage V2 is 24V, the output range of the first power supply 42 is 18V to 22V. In other words, the first power supply 42 can output a drive voltage V1 within a range where the upper limit is 2V (volts) lower than the input voltage V2, and the lower limit is 4V (volts) lower than that upper limit. Alternatively, the first power supply 42 only needs to be able to output a drive voltage V1 within a range where the upper limit is a voltage one voltage value lower than the input voltage V2, and the lower limit is a voltage two voltage values ​​lower than that upper limit.

[0036] The second power supply 43 outputs an input voltage V2 (see Figure 3) to multiple first power supplies 42. For example, each of the second power supplies 43 is a DC-DC converter.

[0037] The temperature sensor 44 detects the temperature of the recording head 31.

[0038] [Configuration of Control Unit 6] Next, the configuration of the control unit 6 will be described with reference to Figure 1.

[0039] As shown in Figure 1, the control unit 6 includes a detection processing unit 51, a first setting processing unit 52, a second setting processing unit 53, an acquisition processing unit 54, a third setting processing unit 55, and a notification processing unit 56.

[0040] Specifically, the ROM 12 of the control unit 6 contains pre-stored operation control programs for enabling the control unit 6 to function as each of the aforementioned processing units. The CPU 11 of the control unit 6 functions as each of the processing units shown in Figure 1 by executing the operation control programs.

[0041] Furthermore, some or all of the processing units included in the control unit 6 may be composed of electronic circuits. Also, the operation control program may be a program that causes multiple processors to function as the processing units shown in Figure 1.

[0042] The detection processing unit 51 detects the ink temperature during the image forming process, in which an image is formed on the sheet using the piezoelectric element 41.

[0043] For example, the detection processing unit 51 acquires the temperature of the recording head 31 detected by the temperature sensor 44 as the ink temperature.

[0044] The image forming apparatus 100 may also be equipped with a sensor capable of directly detecting the ink temperature. In this case, the detection processing unit 51 can use the sensor to detect the ink temperature.

[0045] The first setting processing unit 52 sets the drive voltage V1 for each first power supply 42 based on the detection result from the detection processing unit 51.

[0046] For example, in the image forming apparatus 100, a reference voltage is set in advance for each first power supply 42. The reference voltage is set based on the ink ejection performance of the recording head 31 and the ink ejection performance of the block 40 corresponding to the first power supply 42. The reference voltage corresponding to each of the first power supplies 42 is stored in the storage unit 5.

[0047] Furthermore, in the image forming apparatus 100, table data showing the correspondence between the ink temperature detected by the detection processing unit 51 and the correction value used to correct the reference voltage is stored in the storage unit 5 in advance. In the table data, the correction value is set to "0V (volts)" when the ink temperature detected by the detection processing unit 51 matches a predetermined reference temperature. In addition, the table data defines the correspondence between the ink temperature and the correction value such that the correction value becomes smaller on the negative side as the ink temperature detected by the detection processing unit 51 is higher than the reference temperature. For example, the minimum value of the correction value is "-0.5V (volts)". In addition, the table data defines the correspondence between the ink temperature and the correction value such that the correction value becomes larger on the positive side as the ink temperature detected by the detection processing unit 51 is lower than the reference temperature. For example, the maximum value of the correction value is "+0.5V (volts)".

[0048] When the detection processing unit 51 detects the ink temperature, the first setting processing unit 52 uses the table data to obtain the correction value corresponding to the detected ink temperature. The first setting processing unit 52 also corrects the reference voltage corresponding to each of the first power supplies 42 by adding the obtained correction value to the reference voltage corresponding to each of the first power supplies 42. The first setting processing unit 52 then sets the corrected reference voltage corresponding to each of the first power supplies 42 as the new drive voltage V1 for each of the first power supplies 42.

[0049] For example, the first setting processing unit 52 sets the drive voltage V1 of each of the first power supplies 42 by instructing each of the first power supplies 42 to change the drive voltage V1 it outputs.

[0050] As a result, the drive voltage V1 is adjusted according to the temperature of the ink during the execution of the image forming process.

[0051] The second setting processing unit 53 sets the configurable range of the drive voltage V1 by the first setting processing unit 52 according to a predetermined setting operation. The configurable range is set for each first power supply 42.

[0052] For example, the second setting processing unit 53 displays a setting change screen on the operation display unit 3 in response to a predetermined call operation, where a setting change operation (the setting operation) for the reference voltage corresponding to each first power supply 42 is accepted for each first power supply 42. When the setting change operation is accepted for any of the first power supplies 42 on the setting change screen, the second setting processing unit 53 changes the reference voltage corresponding to that first power supply 42 according to the accepted setting change operation.

[0053] For example, the second setting processing unit 53 changes the reference voltage corresponding to one of the first power supplies 42 by rewriting the information indicating the reference voltage corresponding to one of the first power supplies 42 stored in the memory unit 5.

[0054] For example, the reference voltage corresponding to each of the first power supplies 42 is adjusted when the overall ink ejection performance of the recording head 31 deteriorates due to the aging of the recording head 31. Also, the reference voltage corresponding to each of the first power supplies 42 is adjusted when the variation in ink ejection performance between blocks 40 becomes large due to the aging of the recording head 31.

[0055] Incidentally, in the image forming apparatus 100, the upper or lower limit of the configurable range set by the second setting processing unit 53 may exceed or fall below the outputable range corresponding to the input voltage V2. In this case, if the first setting processing unit 52 sets a drive voltage V1 that exceeds or falls below the outputable range, the image forming process may stop due to an error, or the drive voltage V1 of the upper or lower limit of the outputable range may be output instead of the set drive voltage V1, resulting in problems such as a decrease in the quality of the image formed by the image forming process.

[0056] In contrast, in the image forming apparatus 100 according to an embodiment of the present invention, as described below, it is possible to suppress the drive voltage V1, which is set based on the ink temperature, from exceeding the output range of the first power supply 42.

[0057] The acquisition processing unit 54 acquires the upper and lower limits of each of the settable ranges at a specific timing outside the execution period of the image formation process.

[0058] For example, the specific timing includes the timing when the power to the image forming apparatus 100 is turned on.

[0059] For example, the acquisition processing unit 54 reads the reference voltage corresponding to each of the first power supplies 42 from the storage unit 5. The acquisition processing unit 54 then obtains the upper limit of each of the settable ranges by adding the maximum value of the correction value to each of the read reference voltages. The acquisition processing unit 54 also obtains the lower limit of each of the settable ranges by adding the minimum value of the correction value to each of the read reference voltages.

[0060] The third setting processing unit 55 sets the input voltage V2 based on the highest value and the lowest value among the multiple upper limits acquired by the acquisition processing unit 54 if either the highest value or the lowest value among the multiple lower limits is not within the output range of the first power supply 42.

[0061] Specifically, the third setting processing unit 55 sets the input voltage V2 such that both the highest and lowest values ​​are included in the output range of the first power supply 42 when the difference between the highest and lowest values ​​is less than or equal to the difference between the two limit values ​​of the output range of the first power supply 42 (4V (volts)) (see Figure 4).

[0062] Furthermore, the third setting processing unit 55 sets the input voltage V2 such that, if the difference between the highest value and the lowest value is greater than the difference between the two limit values ​​of the output range of the first power supply 42, the highest value is included in the output range of the first power supply 42, and the difference between the lowest value and the lower limit of the output range of the first power supply 42 is minimized.

[0063] Furthermore, the third setting processing unit 55 may set the input voltage V2 such that, if the difference between the maximum value and the minimum value is greater than the difference between the two limit values ​​of the output range of the first power supply 42, the minimum value is included in the output range of the first power supply 42, and the difference between the maximum value and the upper limit of the output range of the first power supply 42 is minimized.

[0064] Furthermore, if the difference between the highest value and the lowest value is greater than the difference between the two limit values ​​of the output range of the first power supply 42, the third setting processing unit 55 may set the input voltage V2 such that both the highest value and the lowest value are not included in the output range of the first power supply 42, and the difference between the highest value and the upper limit of the output range of the first power supply 42, and the difference between the lowest value and the lower limit of the output range of the first power supply 42, are equal.

[0065] The notification processing unit 56 notifies the system if the difference between the highest value and the lowest value is greater than the difference between the two limit values ​​(4V (volts)) of the output range of the first power supply 42 (see Figure 4).

[0066] For example, if the difference between the highest value and the lowest value is greater than the difference between the two limit values ​​of the output range of the first power supply 42, the notification processing unit 56 displays a message to that effect on the operation display unit 3. This makes it possible to inform the user in advance that a malfunction may occur due to the drive voltage V1, which is set based on the ink temperature, exceeding the output range of the first power supply 42.

[0067] [Drive voltage setting process] The following describes a part of the setting method of the present invention, along with an example of the procedure for the drive voltage setting process executed by the control unit 6 in the image forming apparatus 100, with reference to Figure 5. Here, steps S11, S12, etc. represent the numbers of the processing procedures (steps) executed by the control unit 6. The drive voltage setting process is executed together with the image forming process when the image forming process is performed. Furthermore, the drive voltage setting process is executed for each recording head 31.

[0068] <Step S11> First, in step S11, the control unit 6 determines whether or not the image forming process has been completed.

[0069] At this point, if the control unit 6 determines that the image forming process is complete (Yes side of S11), it terminates the drive voltage setting process. If the image forming process is not complete (No side of S11), the control unit 6 proceeds to step S12.

[0070] <Step S12> In step S12, the control unit 6 determines whether or not the setting timing for the drive voltage V1 has arrived. Here, the setting timing is, for example, a timing that occurs periodically during the execution of the image forming process.

[0071] If the control unit 6 determines that the set timing has arrived (Yes in S12), it proceeds to step S13. If the set timing has not arrived (No in S12), the control unit 6 proceeds to step S11.

[0072] <Step S13> In step S13, the control unit 6 detects the ink temperature. The process in step S13 is an example of the detection steps of the present invention and is performed by the detection processing unit 51 of the control unit 6.

[0073] Specifically, the control unit 6 acquires the temperature of the recording head 31, detected by the temperature sensor 44, as the ink temperature.

[0074] <Step S14> In step S14, the control unit 6 sets the drive voltage V1 for each first power supply 42 based on the detection result from the processing in step S13. The processing in step S14 is an example of the first setting step of the present invention and is performed by the first setting processing unit 52 of the control unit 6.

[0075] Specifically, the control unit 6 uses the table data to obtain the correction value corresponding to the detected ink temperature. The control unit 6 also corrects the reference voltage corresponding to each of the first power supplies 42 by adding the obtained correction value to the reference voltage corresponding to each of the first power supplies 42. Then, the control unit 6 sets the corrected reference voltage corresponding to each of the first power supplies 42 as the new drive voltage V1 for each of the first power supplies 42.

[0076] In the image forming apparatus 100, the settable range of each drive voltage V1 is changed at any timing outside the execution period of the image forming process. The process of changing the settable range of each drive voltage V1 is an example of the second setting step of the present invention and is performed by the second setting processing unit 53 of the control unit 6.

[0077] [Input voltage setting process] Next, with reference to Figure 6, the remainder of the setting method of the present invention will be described along with an example of the procedure for input voltage setting processing performed by the control unit 6 in the image forming apparatus 100. Note that the drive signal adjustment processing is performed for each recording head 31.

[0078] <Step S21> First, in step S21, the control unit 6 determines whether or not the specific timing has arrived.

[0079] If the control unit 6 determines that the specific timing has arrived (Yes in S21), it proceeds to step S22. If the specific timing has not arrived (No in S21), the control unit 6 waits for the specific timing to arrive in step S21.

[0080] <Step S22> In step S22, the control unit 6 acquires the upper and lower limits of each of the settable ranges. The processing in step S22 is an example of the acquisition step of the present invention and is performed by the acquisition processing unit 54 of the control unit 6.

[0081] For example, the control unit 6 reads the reference voltage corresponding to each of the first power supplies 42 from the storage unit 5. Then, the control unit 6 obtains the upper limit of each of the settable ranges by adding the maximum value of the correction value to each of the read reference voltages. The control unit 6 also obtains the lower limit of each of the settable ranges by adding the minimum value of the correction value to each of the read reference voltages.

[0082] <Step S23> In step S23, the control unit 6 determines whether both the highest value among the multiple upper limits and the lowest value among the multiple lower limits obtained by the processing in step S22 are within the output range of the first power supply 42 corresponding to the current input voltage V2.

[0083] Here, if the control unit 6 determines that both the highest and lowest values ​​are within the output range of the first power supply 42 corresponding to the current input voltage V2 (Yes side of S23), it proceeds to step S21. If either or both of the highest and lowest values ​​are not within the output range of the first power supply 42 corresponding to the current input voltage V2 (No side of S23), the control unit 6 proceeds to step S24.

[0084] <Step S24> In step S24, the control unit 6 sets the input voltage V2 based on the maximum value and the minimum value. The processing in step S24 is an example of the third setting step of the present invention and is performed by the third setting processing unit 55 of the control unit 6.

[0085] Specifically, the control unit 6 sets the input voltage V2 such that both the highest and lowest values ​​are included in the output range of the first power supply 42 when the difference between the highest and lowest values ​​is less than or equal to the difference between the two limit values ​​of the output range of the first power supply 42 (4V (volts)) (see Figure 4).

[0086] Furthermore, if the difference between the highest value and the lowest value is greater than the difference between the two limit values ​​of the output range of the first power supply 42, the control unit 6 sets the input voltage V2 such that the highest value is included in the output range of the first power supply 42 and the difference between the lowest value and the lower limit of the output range of the first power supply 42 is minimized.

[0087] In this way, the image forming apparatus 100 acquires the upper and lower limits of each of the settable ranges at the specific timing outside the execution period of the image forming process. If either the highest value among the acquired upper limits or the lowest value among the acquired lower limits is not included in the output range of the first power supply 42, the input voltage V2 is set based on the highest and lowest values. This makes it possible to prevent the drive voltage V1, which is set based on the ink temperature, from exceeding the output range of the first power supply 42.

[0088] The specified timing may also be the timing at which the configurable range is set by the second setting processing unit 53. Alternatively, the specified timing may be the timing at which a predetermined operation is received by the operation display unit 3.

[0089] Furthermore, the second setting processing unit 53 may set (change) either the maximum value of the correction value or the minimum value of the correction value, or both, in response to user operations.

[0090] Furthermore, the recording head 31 may be equipped with a first power supply 42 corresponding to each piezoelectric element 41.

[0091] Furthermore, the recording head 31 may be equipped with a single first power supply 42 that corresponds to all piezoelectric elements 41 included in the recording head 31.

[0092] [Notes on the invention] The following is an overview of the invention extracted from the above-described embodiments. Note that each configuration and processing function described below can be selected and combined as desired.

[0093] <Note 1> An image forming apparatus comprising: a discharge unit that discharges ink from a nozzle in response to a preset drive voltage input; a first power supply that outputs a drive voltage within an output range corresponding to a preset input voltage to the discharge unit in response to a preset input voltage input; a detection processing unit that detects the temperature of the ink during the execution of an image forming process in which an image is formed on a sheet using the discharge unit; a first setting processing unit that sets the drive voltage based on the detection result by the detection processing unit; a second setting processing unit that sets the configurable range of the drive voltage by the first setting processing unit in response to a preset setting operation; an acquisition processing unit that acquires the upper and lower limits of the configurable range at a specific timing outside the execution period of the image forming process; and a third setting processing unit that sets the input voltage based on the upper and lower limits if either the upper or lower limit acquired by the acquisition processing unit is not included in the output range.

[0094] <Note 2> The image forming apparatus according to Appendix 1, further comprising a second power supply that outputs the input voltage to a plurality of first power supplies, wherein the configurable range is set for each first power supply, the first setting processing unit sets the drive voltage for each first power supply based on the detection result by the detection processing unit, the acquisition processing unit acquires the upper and lower limits of each of the configurable ranges at a specific timing, and the third setting processing unit sets the input voltage based on the highest and lowest values ​​if either the highest value among the plurality of upper limits acquired by the acquisition processing unit or the lowest value among the plurality of lower limits is not included in the outputable range.

[0095] <Note 3> The image forming apparatus according to Appendix 1 or 2, wherein the specified timing includes the timing when the power to the image forming apparatus is turned on.

[0096] <Note 4> The image forming apparatus according to any one of the appendices 1 to 3, wherein the specified timing includes the timing at which the settable range is set by the second setting processing unit.

[0097] <Note 5> An image forming apparatus according to any one of the appendices 1 to 4, comprising a notification processing unit that notifies the user if the difference between the upper limit and the lower limit is greater than the difference between the two limit values ​​of the outputtable range.

[0098] <Note 6> A setting method performed in an image forming apparatus comprising: an ejection unit that ejects ink from a nozzle in response to a preset drive voltage input; and a first power supply that outputs a drive voltage within an output range corresponding to a preset input voltage to the ejection unit in response to a preset input voltage input, the setting method comprising: a detection step of detecting the temperature of the ink during the execution of an image forming process in which an image is formed on a sheet using the ejection unit; a first setting step of setting the drive voltage based on the detection result of the detection step; a second setting step of setting the settable range of the drive voltage according to a preset setting operation; an acquisition step of acquiring the upper and lower limits of the settable range at a specific timing outside the execution period of the image forming process; and a third setting step of setting the input voltage based on the upper and lower limits if either the upper or lower limit acquired by the acquisition step is not included in the output range. [Explanation of Symbols]

[0099] 1. Sheet transport section 2 Image forming unit 3 Operation display section 4. Communications Department 5 Storage section 6 Control Unit 11 CPU 12 ROM 13 RAM 20 line heads 30 nozzle groups 31 Recording head 32 Nozzle surface 33 nozzles 40 blocks 41 Piezoelectric element 42 1st power supply 43 2nd power supply 44 Temperature Sensors 51 Detection Processing Unit 52 First setting processing unit 53 Second setting processing unit 54 Acquisition Processing Unit 55 Third setting processing unit 56 Notification Processing Unit 100 Image forming apparatus

Claims

1. A dispensing unit that ejects ink from the nozzle in accordance with a preset drive voltage input, A first power supply outputs a drive voltage within an output range corresponding to a preset input voltage to the discharge unit, and During the execution of the image forming process in which an image is formed on a sheet using the ejection unit, a detection processing unit is provided to detect the temperature of the ink, A first setting processing unit sets the drive voltage based on the detection result by the detection processing unit, A second setting processing unit sets the configurable range of the drive voltage by the first setting processing unit in accordance with a predetermined setting operation, An acquisition processing unit that acquires the upper and lower limits of the settable range at a specific timing outside the execution period of the image forming process, If either the upper limit value or the lower limit value acquired by the acquisition processing unit does not fall within the output range, a third setting processing unit sets the input voltage based on the upper limit value and the lower limit value, An image forming apparatus equipped with the following features.

2. The system includes a second power supply that outputs the input voltage to a plurality of the first power supplies, The aforementioned configurable range is set for each of the first power supplies, The first setting processing unit sets the drive voltage for each of the first power supplies based on the detection result by the detection processing unit. The acquisition processing unit acquires the upper and lower limits of each of the settable ranges at the specified timing. The third setting processing unit sets the input voltage based on the highest value and the lowest value if either the highest value among the plurality of upper limits acquired by the acquisition processing unit or the lowest value among the plurality of lower limits is not included in the output range. The image forming apparatus according to claim 1.

3. The aforementioned specific timing includes the timing when the power to the image forming apparatus is turned on. The image forming apparatus according to claim 1 or 2.

4. The aforementioned specific timing includes the timing at which the configurable range is set by the second setting processing unit. The image forming apparatus according to claim 1 or 2.

5. The system includes a notification processing unit that notifies the user if the difference between the upper limit and the lower limit is greater than the difference between the two limit values ​​of the output range. The image forming apparatus according to claim 1 or 2.

6. A setting method performed in an image forming apparatus comprising: an ejection unit that ejects ink from a nozzle in response to a preset drive voltage input; and a first power supply that outputs a drive voltage within an output range corresponding to the input voltage to the ejection unit in response to a preset input voltage input; During the execution of the image forming process in which an image is formed on a sheet using the aforementioned ejection unit, a detection step is performed to detect the temperature of the ink, A first setting step in which the drive voltage is set based on the detection result from the above detection step, A second setting step sets the configurable range of the drive voltage according to a predetermined setting operation, An acquisition step to acquire the upper and lower limits of the configurable range at a specific timing outside the execution period of the image forming process, If either the upper limit value or the lower limit value obtained in the acquisition step is not included in the output range, a third setting step is performed to set the input voltage based on the upper limit value and the lower limit value, Instructions for setting up, including the method described.

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