JP6299359B2 - Image forming apparatus and program - Google Patents

Description

  The present invention relates to an image forming apparatus, and more particularly to control of idle ejection in an image forming apparatus.

  A line-type ink jet printer is an image forming apparatus that performs printing in units of lines by simultaneously driving a plurality of print heads arranged in parallel in the width direction of a recording sheet. A line-type inkjet printer has a lower head drive frequency than a serial machine that performs printing by moving one print head in the width direction (main scanning direction) of the recording paper. Power consumption is small.

  On the other hand, as a maintenance / recovery operation for maintaining / recovering the performance of the print head, an ink jet printer uses ink droplets that do not contribute to image formation before printing or between papers (empty discharge) to increase the viscosity of ink. Drain from the nozzle. However, in the case of a line-type ink jet printer, there is a problem that the power consumption of the head drive circuit related to idle ejection becomes excessive because the idle ejection must be performed for a plurality of print heads.

  In this regard, Japanese Patent Laid-Open No. 2005-238780 (Patent Document 1) discloses an ink jet type image forming apparatus that reduces the frequency of idle ejection by determining the number of idle ejections required according to the head temperature.

  SUMMARY An advantage of some aspects of the invention is that it provides a novel image forming apparatus capable of suppressing power consumption of a head driving circuit.

  As a result of intensive studies on a novel image forming apparatus capable of suppressing the power consumption of the head drive circuit, the present inventor has conceived the following configuration and arrived at the present invention.

  That is, according to the present invention, there is provided an image forming apparatus in which a plurality of print heads are arranged in parallel in the width direction of the recording paper, and a nozzle determination unit that determines in advance the nozzles of the print head involved in printing of image data. , An idle discharge execution nozzle determining unit that determines a nozzle that performs idle discharge from among the nozzles that are involved in the print of the image data, and the idle discharge of the nozzle determined by the idle discharge execution nozzle determination unit is printed on the image data An image forming apparatus is provided that includes an empty discharge execution unit that is executed before the operation.

  As described above, according to the present invention, a novel image forming apparatus capable of suppressing the power consumption of the head drive circuit is provided.

1 is a diagram illustrating an internal configuration of an ink jet image forming apparatus according to a first embodiment. FIG. 3 is a diagram illustrating an arrangement mode of a print head. The conceptual diagram for demonstrating the method to determine the implementation target nozzle of idle discharge. The conceptual diagram for demonstrating the method which divides | segments and implements empty discharge. The flowchart which shows the idle discharge control in 1st Embodiment. 1 is a system configuration diagram of an ink jet image forming apparatus according to a first embodiment. 1 is a functional block diagram of an ink jet image forming apparatus according to a first embodiment. The system block diagram of the inkjet type image forming apparatus of 2nd Embodiment. The flowchart which shows the process for setting the reduction coefficient (alpha) for reducing the number of implementation object nozzles. The flowchart which shows the idle discharge control in 2nd Embodiment. The functional block diagram of the inkjet type image forming apparatus of 2nd Embodiment.

  Hereinafter, although this invention is demonstrated with embodiment, this invention is not limited to embodiment mentioned later. In the drawings referred to below, the same reference numerals are used for common elements, and the description thereof is omitted as appropriate.

(First embodiment)
FIG. 1 shows an internal configuration of a line-type ink jet image forming apparatus 100 according to the first embodiment of the present invention. As shown in FIG. 1, in the ink jet image forming apparatus 100 according to the present embodiment, a recording sheet 101 stacked on a recording sheet stacking unit (pressure plate) of a sheet feeding tray 102 is opposed to a sheet feeding roller 104. Then, the separation pad 105 provided in an energized state is separated and fed one by one from the recording paper stacking unit to the conveyance unit.

  The conveyance unit conveys the recording sheet by electrostatic adsorption and conveys the recording sheet fed from the recording sheet stacking unit by 90 ° and follows the conveyance belt. A guide 107, a tip pressing roller 108 urged toward the conveying belt 106 by a pressing member, and a charging roller 109 as a charging unit for charging the surface of the conveying belt 106 are provided. The charging roller 109 is disposed so as to come into contact with the surface layer of the conveyor belt 106 and to rotate following the rotation of the conveyor belt 106.

  The conveyor belt 106, which is an endless belt, is stretched between the conveyor roller 110 and the tension roller 111, and is configured to circulate in the belt conveyance direction indicated by the arrow. A plurality of print heads 112 are arranged above the transport belt 106 in the direction perpendicular to the belt transport direction indicated by the arrow (the depth direction on the paper surface), and the ink supplied from the ink supply pipe 103 is stored in the plurality of print heads. 112 is configured to be discharged all at once onto the recording paper 101 conveyed on the conveying belt 106.

  FIG. 2 shows an arrangement mode of eight print heads 112 (heads 1 to 8) mounted on the ink jet image forming apparatus 100. As shown in FIG. 2, in the ink jet image forming apparatus 100 employing the line system, eight print heads 112 are arranged in parallel in four rows in the width direction of the recording paper (perpendicular to the paper transport direction). In addition, each of the eight print heads 112 is configured to realize line-by-line printing by ejecting ink at a fixed position. 2 is merely an example, and the number of print heads is not limited to eight. Here, each print head 112 has nozzles for ejecting ink of each color of yellow (Y), magenta (M), cyan (C), and black (K) as shown in an enlarged view in FIG. A total of four rows are arranged one by one. 2 is merely an example, and the nozzle arrangement may be a staggered arrangement.

  A guide member (not shown) is arranged on the back side of the conveyance belt 106 corresponding to the printing area of the print head 112, and the conveyance belt 106 is pushed up by the guide member to maintain high-precision flatness of the conveyance belt 106. Is configured to do.

  The recording paper 101 printed with ink ejected from the print head 112 is separated from the transport belt 106 by the separation claw 113 and stocked on the paper discharge tray 114. The double-sided paper feeding unit 115 that is detachably attached to the back surface of the apparatus main body is configured to take in the recording paper 101 returned by the reverse rotation of the conveying belt 106, invert it, and supply it to the conveying belt 106 again. ing.

  The outline of the internal configuration of the ink jet image forming apparatus 100 according to the present embodiment has been described above. Next, the idle ejection control according to the present embodiment will be described.

  The ink jet image forming apparatus 100 according to the present embodiment does not contribute to image formation as a maintenance / recovery operation for maintaining / recovering the performance of the print head before printing or between sheets when a plurality of pages are continuously printed. Ink that has been thickened (deformed) by discharging ink droplets is discharged from the nozzle. Hereinafter, such ink droplet ejection is referred to as “empty ejection”. In the present embodiment, in the maintenance / recovery operation, the number of idle ejections is determined by omitting idle ejection of nozzles that are not involved in printing image data, instead of uniformly performing idle ejection for all nozzles of all print heads 112. To the minimum necessary. In addition, the maximum power consumption of the head drive circuit related to idle ejection is suppressed by performing idle ejection by dividing it into a predetermined number rather than simultaneously performing idle ejection of all nozzles involved in image data printing. To do. The contents will be specifically described below.

  Here, a description will be given by taking, as an example, idle ejection performed in a period immediately before printing the image data 500 shown in FIG. Note that the immediately preceding period referred to here is that when the image data 500 is a part of print data composed of a plurality of pages, the printing of other image data immediately before the image data 500 is completed. It means the period before printing starts (that is, between paper).

  Here, the image data 500 can be divided into five regions along the width direction of the recording paper based on the type of ink used for the printing. Specifically, as shown in FIG. 3, in order from the left side of the page, an area that does not use all colors (hereinafter referred to as an all color non-use area) and an area that uses all colors (hereinafter referred to as an all color use area). , An area using only cyan (C) (hereinafter referred to as an area where only C is used), an area using only magenta (M) (hereinafter referred to as an area where only M is used), and an area not using all colors. be able to.

  Here, in FIG. 3, the image data 500 and the positions of the nozzles of the eight print heads 112 (heads 1 to 8) in charge of printing are shown in association with each other. In the example shown in FIG. 3, the head 1 is scheduled to print “all color unused area” and “all color used area”, and the head 2 and head 3 are scheduled to print “all color used area”. The head 4 is scheduled to print “all-color use area” and “C-only use area”, the head 5 is scheduled to print “C-only use area”, and the head 6 is “C-only use area” and “ “M only use area” is scheduled to be printed, head 7 is scheduled to print “M only use area”, and head 8 is scheduled to print “C only use area” and “all color non-use area”. I can see that there is.

  In this case, in the present embodiment, the nozzles to be subjected to the idle discharge are determined as follows. That is, in the head 1, the idle ejection of all nozzles scheduled to print the “all color unused area” is omitted, and all nozzles (4 colors) scheduled to print the “all color used area” are idle ejected. The target of. In order to show this, in FIG. 3, for the head 1, the nozzles for which the idle ejection is omitted are indicated by white circles, and are indicated by the circles that are filled with the color of the ink that ejects the nozzles that are the targets for the idle ejection. (Hereafter, the same applies to other heads).

  Further, in the head 2 and the head 3, all nozzles (four colors) are targets for idle ejection. Further, in the head 4, all nozzles (4 colors) involved in the “all-color use area” are subjected to idle discharge, and cyan (C) nozzles among nozzles scheduled to be in charge of the “C-only use area” Only the target of idle discharge. Further, in the head 5, only cyan (C) nozzles are the targets of idle ejection. Further, in the head 6, only the cyan (C) nozzle among the nozzles scheduled to be assigned to the “C only use area” is set as the target of idle ejection, and magenta among the nozzles scheduled to be assigned to the “M only use area”. Only the nozzle (M) is the target of idle discharge. Further, in the head 7, only magenta (M) nozzles are the targets of idle ejection. Further, in the head 8, only the magenta (M) nozzles among the nozzles scheduled to be in charge of the “M only use area” are subjected to empty ejection, and all nozzles scheduled to be in charge of the “all color non-use area”. The idle discharge is omitted.

  As described above, according to the first embodiment, the nozzles used for printing the image data to be printed immediately after are determined in advance, and the idle ejection of the other nozzles is omitted, thereby eliminating the idle ejection. Such power consumption can be minimized.

  In addition, in this embodiment, in order to suppress the maximum power consumption of the head drive circuit related to the idle ejection, the idle ejection of all nozzles that are the targets of the idle ejection is divided into multiple times and shifted in time. To do. Specifically, an allowable value of the maximum power consumption of the head drive circuit related to idle ejection is determined in advance, and the maximum number of nozzles [Nmax] that can simultaneously perform idle ejection within a range not exceeding the allowable value Sought in advance. Then, [Nmax] nozzles are sequentially discharged for all the nozzles to be subjected to the idle discharge.

  If [Nmax] = 22, 59 target nozzles of the head 4 shown in FIG. 3 are divided into three nozzle groups (22, 22, 15) as shown in FIG. Then, the idle discharge is performed by shifting the time in three times. In practice, since all implementation target nozzles of the plurality of heads 112 are divided based on [Nmax], for example, in the example illustrated in FIG. 3, implementation target nozzles determined for eight heads 112. When dividing (total 253) with [Nmax] = 22, 11 nozzle groups consisting of 22 nozzles and 1 nozzle group consisting of 11 nozzles are defined, for a total of 12 nozzle groups. Is done. Accordingly, it is naturally possible to define a nozzle group across two or more heads.

  As described above, according to the first embodiment, since the idle ejection of all the nozzles to be subjected to the idle ejection is performed in a plurality of times and shifted in time, the maximum consumption of the head drive circuit related to the idle ejection is performed. Electric power can be suppressed.

  The content of the idle discharge control in the present embodiment has been described above. A specific flow of the idle discharge control in the present embodiment will be described based on the flowchart shown in FIG. In the following description, the system configuration diagram of the inkjet image forming apparatus 100 shown in FIG. 6 will be referred to as appropriate. In FIG. 6, constituent elements related to the gist of the present invention are exclusively shown, and the remaining constituent elements are not shown.

  First, the maximum number [Nmax] of the number of nozzles that can simultaneously perform idle ejection within a range that does not exceed the allowable value of the maximum power consumption of the head drive circuit for idle ejection is set in the ASIC 10 (step 101).

  When the print data is input to the image forming apparatus 100 from an external device exemplified as the PC 300, the ASIC 10 extracts the image data from the print data and stores it in the memory IC 12. Thereafter, the ASIC 10 determines the nozzles to be subjected to the idle ejection in accordance with the procedure described in FIG. 3 based on the contents of the image data stored in the memory IC 12, and sets the number [N] in the counter (step 102).

  In subsequent step 103, it is determined whether or not the counter value [N] set in step 102 is equal to or smaller than [Nmax]. If it is determined that [N] is equal to or smaller than [Nmax] (step 103, Yes). ), The process proceeds to step 104, and the idle discharge of the nozzle group composed of [N] nozzles is performed all at once, and the process is terminated. On the other hand, when it is determined in step 103 that the counter value [N] is not less than [Nmax] (step 103, No), the process proceeds to step 105.

  In step 105, among the target nozzles determined in step 102, idle discharge is simultaneously performed for a nozzle group composed of [Nmax] nozzles that have not been idlely discharged. Thereafter, [Nmax] is decremented from the current counter value to update the counter value (step 106), and then the process returns to step 103 again. The series of processes described above is repeated until it is determined in step 103 that the counter value [N] is equal to or smaller than [Nmax], and the counter value [N] is determined to be equal to or smaller than [Nmax]. (Step 103, Yes), the [N] nozzles (that is, the last nozzle group) are ejected all at once (Step 104), and the process is terminated.

  Specifically, the series of processing described above is performed as follows. In other words, the ASIC 10 determines the target nozzles based on the content of the image data, and generates a head control signal for ejecting these nozzles in order by [Nmax]. The ASIC 10 transmits the generated head control signal to the head driver 14 together with the head drive waveform. The head driver 14 generates a head drive waveform for each nozzle from the head control signal and the head drive waveform received from the ASIC 10 and outputs them to the print head 112. As a result, during the period before printing the image data, the [Nmax] nozzles are sequentially ejected in order for all the nozzles determined in step 102.

  FIG. 7 shows functional blocks constituting idle ejection control means in the ink jet image forming apparatus 100 of the first embodiment described above. As shown in FIG. 7, the idle ejection control unit in the inkjet image forming apparatus 100 of the first embodiment includes a nozzle determination unit 20, an idle ejection execution nozzle determination unit 22, and an idle ejection execution unit 24. The In the present embodiment, the nozzle determination unit 20 determines in advance the nozzles of the print head involved in printing image data, and the idle ejection execution nozzle determination unit 22 performs idle ejection from among the nozzles involved in printing image data. Determine the nozzle to be implemented. Then, the idle discharge execution unit 24 performs the idle discharge of the nozzles determined by the idle discharge execution nozzle determination unit 22 based on the value of [Nmax] set in the storage unit 25 before executing the printing of the image data. To do. Each functional unit described above is realized by the cooperation of the ASIC 10, the memory IC 12, and the head driver 14 shown in FIG.

  As described above, the nozzles involved in the printing of the image data are the target nozzles for the idle ejection, and the idle ejection is performed in a plurality of times, thereby suppressing the maximum power consumption of the head driving circuit related to the idle ejection. Although the first embodiment of the invention has been described, a configuration for reducing the number of target nozzles according to the temperature state in the apparatus is added to the configuration of the first embodiment described above. A second embodiment of the present invention will be described.

(Second Embodiment)
FIG. 8 shows functional blocks of a line-type ink jet image forming apparatus 200 according to the second embodiment of the present invention. In FIG. 8, the components related to the gist of the present invention are exclusively shown, and the remaining components are not shown.

  As shown in FIG. 8, the configuration of the ink jet image forming apparatus 200 of the present embodiment is the ink jet image forming apparatus of the first embodiment, except that a temperature sensor 16 is provided to measure the temperature in the apparatus. Common to that of the device 100.

  In the present embodiment, an analog signal indicating the temperature in the apparatus measured by the temperature sensor 16 is input to the ASIC 10, and the ASIC 10 determines the number of target nozzles according to the temperature level in the apparatus. Is set to a reduction coefficient α (α is a real number between 0 and 1). Hereinafter, the process for setting the reduction coefficient α will be described based on the flowchart shown in FIG. In the following description, the system configuration diagram shown in FIG. 8 is referred to as appropriate.

  When the ASIC 10 acquires the temperature measurement value from the temperature sensor 16 (step 201), the ASIC 10 determines the temperature level based on the acquired measurement value, and stores the determined temperature level in the memory IC 12 (step 202).

  Specifically, the ASIC 10 determines that the temperature level is “30 ° C.” when the measured value input from the temperature sensor 16 is 30 ° C. or higher, and the measured value input from the temperature sensor 16 is 25 ° C. or higher 30 When the temperature is less than ° C., the temperature level is determined as “25 ° C.”, and when the measured value input from the temperature sensor 16 is 20 ° C. or higher and lower than 25 ° C., the temperature level is determined as “20 ° C.” When the measured value input from 16 is less than 20 ° C., the temperature level is determined to be “15 ° C.”. Then, the ASIC 10 accumulates the determined temperature level in the memory IC 12 in time series.

  Next, after reading the latest temperature level from the memory IC 12 (step 203), the ASIC 10 determines whether or not the temperature level is “30 ° C.” (step 204). As a result, when the read temperature level is “30 ° C.” (step 204, Yes), the temperature level accumulated in the memory IC 12 during the most recent predetermined period (eg, 100 ms) is read (step 205). It is determined whether or not there is a temperature level other than “30 ° C.” among the plurality of temperature levels (step 206).

  As a result, if there is a temperature level other than “30 ° C.” in the read temperature level (step 206, Yes), the reduction coefficient α is set to “1” (step 207), and the process is terminated. . On the other hand, when there is no temperature level other than “30 ° C.” in the read temperature level (No at Step 206), the reduction coefficient α is set to “0” (Step 208), and the process is terminated.

  If the read temperature level is not “30 ° C.” in the determination in the previous step 204 (No in step 204), it is determined whether or not the temperature level is “25 ° C.” (step 209). As a result, when the read temperature level is “25 ° C.” (step 209, Yes), the temperature level stored in the memory IC 12 is read (step 210) and read out during the latest predetermined period (eg, 100 ms). It is determined whether or not a temperature level other than “25 ° C.” exists among the plurality of temperature levels (step 211).

  As a result, when there is a temperature level other than “25 ° C.” in the read temperature level (step 211, Yes), the reduction coefficient α is set to “1” (step 212), and the process is terminated. . On the other hand, when there is no temperature level other than “25 ° C.” in the read temperature level (No at step 211), the reduction coefficient α is set to “0.25” (step 213), and the process is terminated.

  If the read temperature level is not “25 ° C.” in the previous step 209 (step 209, No), it is determined whether or not the temperature level is “20 ° C.” (step 214). As a result, when the read temperature level is “20 ° C.” (step 214, Yes), the temperature level stored in the memory IC 12 is read (step 215) and read out during the latest predetermined period (eg, 100 ms). It is determined whether or not a temperature level other than “20 ° C.” exists among the plurality of temperature levels (step 216).

  As a result, when there is a temperature level other than “20 ° C.” in the read temperature level (step 216, Yes), the reduction coefficient α is set to “1” (step 217), and the process is terminated. . On the other hand, when there is no temperature level other than “20 ° C.” in the read temperature level (No in step 216), the reduction coefficient α is set to “0.5” (step 218), and the process is terminated.

  On the other hand, if the read temperature level is not “20 ° C.” in the determination in the previous step 214 (No in step 214), the reduction coefficient α is set to “1” (step 219), and the process is terminated. To do.

  In short, in the present embodiment, as a result of illuminating the latest temperature level with the temperature level accumulated in the most recent predetermined period, when a temperature level other than the latest temperature level exists in the accumulated temperature level, A temperature change has occurred in the apparatus, and it is estimated that there is a high probability that the ink will thicken (degenerate) due to the influence, and the reduction coefficient α is set to “1” so as not to reduce the number of target nozzles. On the other hand, if there is no temperature level other than the latest temperature level among the accumulated temperature levels, it is estimated that there is no temperature change in the apparatus and the probability of ink thickening (degeneration) is low. Thus, the reduction coefficient α is set to a value corresponding to the current temperature level.

  Specifically, when the temperature level changes, the reduction coefficient α is set to “1” so as not to reduce the number of nozzles that perform idle ejection, and the temperature level increases as the temperature level does not change. A reduction coefficient is set such that the number of nozzles that perform idle ejection is reduced.

  In the above-described example, when the current temperature level is “30 ° C.”, the reduction coefficient α is set to “0”. However, this is not the case in an apparatus maintained at a high temperature of 30 ° C. or higher. Since the probability of increasing the viscosity is low, the purpose of this is to completely eliminate idle ejection. Further, in the above-described example, when the current temperature level is “25 ° C.”, the reduction coefficient α is set to “0.25”, and when the current temperature level is “20 ° C.”, the reduction coefficient α is set to It is set to “0.5”. This is because the probability that the ink thickens gradually increases as the temperature in the apparatus decreases, and accordingly, the value of the reduction coefficient α is increased accordingly (that is, the number of implementation target nozzles is not further reduced). Is the purpose. When the read temperature level is not “20 ° C.” in the determination in step 214 (that is, when the read temperature level is “15 ° C.”), the reduction coefficient α is set to “1”. The reason is that, in an environment where the inside of the apparatus is maintained at a low temperature of less than 20 ° C., the viscosity of ink tends to increase, so that the number of target nozzles is not reduced.

  The ASIC 10 repeatedly executes the process shown in FIG. 9 at a constant cycle (for example, every 1 ms). As a result, the value of the reduction coefficient α set in the ASIC 10 changes every time in the apparatus according to the temperature change.

  The processing for setting the reduction coefficient α for reducing the number of implementation target nozzles has been described above. Next, FIG. 10 shows a specific flow of idle discharge control using the reduction coefficient α in the present embodiment. It demonstrates based on the flowchart to show.

  First, the maximum value [Nmax] of the number of nozzles that can simultaneously perform idle ejection within a range that does not exceed the allowable value of the maximum power consumption of the head drive circuit for idle ejection is set in the ASIC 10 (step 301).

  In response to the input of the print data from the PC 300 to the image forming apparatus 200, the ASIC 10 extracts the image data from the print data, stores it in the memory IC 12, and then based on the content of the image data stored in the memory IC 12. Nozzle candidates (hereinafter referred to as candidate nozzles) for performing idle ejection are selected, and the number [N] is set in the counter (step 302). The candidate nozzles here correspond to the implementation target nozzles in the first embodiment, and are selected by the same method as described in FIG.

  In the following step 303, the number of candidate nozzles set in the counter [N] is multiplied by the reduction coefficient α set at that time (the decimal part is rounded up or down based on a predetermined rule). Update the value.

  In subsequent step 304, candidate nozzles are selected from the candidate nozzles selected in step 302 by the number [N] set in the counter, and are determined as idle discharge target nozzles. For example, when the reduction coefficient α used in step 303 is “0”, N = 0, and in this case, the number of execution target nozzles is 0. Therefore, all candidate nozzles selected in step 302 are set as execution target nozzles. Is not determined (that is, empty discharge is omitted entirely). If the reduction coefficient α used in step 303 is “0.25”, the nozzles corresponding to 3/4 of the candidate nozzles selected in step 302 are thinned out based on a predetermined rule, and the remaining 1 The number of nozzles corresponding to / 4 is determined as the implementation target nozzle. Similarly, when the reduction coefficient α used in step 303 is “0.5”, the number of nozzles corresponding to 1/2 of the number is reduced from the candidate nozzles selected in step 302 based on a predetermined rule. The number of nozzles corresponding to the remaining half is determined as the target nozzle. When the reduction coefficient α used in step 303 is “1”, all candidate nozzles selected in step 302 are determined as implementation target nozzles.

  In the subsequent step 305, it is determined whether or not the counter value [N] updated in step 303 is equal to or smaller than [Nmax]. If it is determined that [N] is equal to or smaller than [Nmax] (step 305, Yes). ), The process proceeds to step 306, and among the target nozzles determined in step 304, the nozzle group consisting of [N] nozzles is discharged all at once, and the process ends. On the other hand, if it is determined in step 305 that the counter value [N] is not less than [Nmax] (step 305, No), the process proceeds to step 307.

  In step 307, among the target nozzles determined in step 304, the nozzle group consisting of [Nmax] nozzles that have not been idle-discharged is simultaneously executed. Thereafter, [Nmax] is decremented from the current counter value to update the counter value (step 308), and then the process returns to step 305 again. The series of processes described above is repeated until it is determined in step 305 that the counter value [N] is equal to or smaller than [Nmax], and the counter value [N] is determined to be equal to or smaller than [Nmax]. (Step 305, Yes), the [N] nozzles (that is, the last nozzle group) are ejected all at once (Step 306), and the process is terminated.

  As described above, according to the second embodiment, in addition to omitting the idle ejection of the nozzles that are not involved in printing the image data that is scheduled to be printed immediately thereafter, the nozzles that are involved in the printing of the image data are also included in the apparatus. Depending on the temperature state, the omission of part or all of the idle ejection is appropriately determined, so that the power consumption related to idle ejection can be minimized.

  FIG. 11 shows functional blocks constituting the idle ejection control means in the ink jet image forming apparatus 200 of the second embodiment described above. As shown in FIG. 11, the idle ejection control unit in the inkjet image forming apparatus 200 of the second embodiment includes a nozzle determination unit 20, an idle ejection execution nozzle determination unit 22, an idle ejection execution unit 24, and a reduction coefficient setting. A unit 26 and a temperature level determination unit 28 are included. In the present embodiment, the nozzle determination unit 20 determines in advance the nozzles of the print head involved in printing image data, and the idle ejection execution nozzle determination unit 22 performs idle ejection from among the nozzles involved in printing image data. Determine the nozzle to be implemented. On the other hand, the reduction coefficient setting unit 26 reduces the number of nozzles that perform the idle discharge according to the temperature level in the apparatus determined by the temperature level determination unit 28 based on the measurement value of the temperature sensor 16. , And the idle discharge execution nozzle determination unit 22 determines omission of some or all of the nozzles involved in the printing of the image data based on the set reduction coefficient α. Then, the idle discharge execution unit 24 performs the idle discharge of the nozzles determined by the idle discharge execution nozzle determination unit 22 based on the value of [Nmax] set in the storage unit 25 before executing the printing of the image data. To do. Each functional unit described above is realized by the cooperation of the ASIC 10, the memory IC 12, and the head driver 14 shown in FIG.

  Although the present invention has been described with the embodiment, the present invention is not limited to the above-described embodiment. For example, in the above-described embodiment, the configuration that realizes the function constituting the idle ejection control means by the cooperation of the ASIC 10, the memory IC 12, and the head driver 14 has been described. , C ++, C #, Java (registered trademark), etc., which can be realized by a device executable program, such as a hard disk device, CD-ROM, MO, DVD, flexible disk, EEPROM, EPROM, etc. It can be stored in a device-readable recording medium and distributed, and can be transmitted via a network in a format that other devices can. In addition, it is included in the scope of the present invention as long as the effects and effects of the present invention are exhibited within the scope of embodiments that can be considered by those skilled in the art.

10 ... ASIC
12 ... Memory IC
DESCRIPTION OF SYMBOLS 14 ... Head driver 16 ... Temperature sensor 20 ... Nozzle determination part 22 ... Empty discharge execution nozzle determination part 24 ... Empty discharge execution part 25 ... Memory | storage part 26 ... Reduction coefficient setting part 28 ... Temperature level determination part 100,200 ... Inkjet image Forming apparatus 101 ... Recording paper 102 ... Feed tray 103 ... Ink supply pipe 104 ... Feed roller 105 ... Separation pad 106 ... Conveying belt 107 ... Conveying guide 108 ... Tip press roller 109 ... Charging roller 110 ... Conveying roller 111 ... Tension Roller 112 ... Print head 113 ... Separation claw 114 ... Paper discharge tray 115 ... Double-sided paper feed unit 500 ... Image data

JP 2005-238780 A

Claims (8)

An image forming apparatus having a plurality of print heads arranged in parallel in the width direction of a recording sheet,
Nozzle determination means for determining in advance the nozzles of the print head involved in printing image data;
An idle discharge execution nozzle determining means for determining a nozzle for performing idle discharge from among the nozzles involved in the printing of the image data;
The idle discharge execution means for executing the idle discharge of the nozzle determined by the idle discharge execution nozzle determining means before executing the printing of the image data;
Temperature level determining means for determining a temperature level in the apparatus;
Reduction coefficient setting means for setting a reduction coefficient for reducing the number of nozzles that perform idle discharge according to the temperature level,
The idle discharge execution nozzle determining means includes
Determining omission of some or all of the nozzles involved in printing of the image data based on the set reduction coefficient;
Image forming apparatus. The reduction coefficient setting means includes
Setting the reduction coefficient such that the number of nozzles that perform idle ejection decreases as the temperature level increases;
The image forming apparatus according to claim 1 . The reduction coefficient setting means includes
Setting the reduction factor so as not to reduce the number of nozzles that perform idle ejection when the temperature level changes,
The image forming apparatus according to claim 1 or 2. The idle discharge execution means divides and implements the idle discharge of the plurality of nozzles determined by the idle discharge execution nozzle determination means by a predetermined number.
The image forming apparatus according to any one of claims 1 to 3 . As the predetermined number, the number of nozzles is set so that the maximum power consumption of the print head when the idle discharge of the predetermined number of nozzles is simultaneously performed does not exceed a predetermined allowable value.
The image forming apparatus according to claim 4 . A computer for controlling an image forming apparatus in which a plurality of print heads are arranged in parallel in the width direction of a recording sheet,
Nozzle determination means for determining in advance the nozzles of the print head involved in printing image data,
An idle discharge execution nozzle determining means for determining a nozzle that performs idle discharge from among the nozzles involved in the printing of the image data;
An idle discharge execution means for executing the idle discharge of the nozzle determined by the idle discharge execution nozzle determining means before executing the printing of the image data;
Temperature level determination means for determining a temperature level in the apparatus;
A reduction coefficient setting means for setting a reduction coefficient for reducing the number of nozzles that perform idle ejection according to the temperature level;
A program that functions as
The idle discharge execution nozzle determining means includes
Determining omission of some or all of the nozzles involved in printing of the image data based on the set reduction coefficient;
A computer executable program. The idle discharge execution means divides and implements the idle discharge of the plurality of nozzles determined by the idle discharge execution nozzle determination means by a predetermined number.
The program according to claim 6 . As the predetermined number, the number of nozzles is set so that the maximum power consumption of the print head when the idle discharge of the predetermined number of nozzles is simultaneously performed does not exceed a predetermined allowable value.
The program according to claim 7 .