JP2007323003A - Printer and calculating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer and a calculating method for more accurately calculating the number of printable sheets in the case a toner amount is equal to or below a fixed remaining amount. <P>SOLUTION: The remaining amount of the toner packed in a toner cartridge is detected, and whether the toner is in an near-end state or not is detected. When the toner is in the near-end state, the number of printable sheets (PV number) that can be usually printed by using the remaining toner amount is calculated based on the toner amount used to perform printing output processing of the unit number of sheets, and then, the printing output processing is performed within the extent of the calculated number of printable sheets. In the case the output number of sheets to be printed exceeds the PV number, the printing output processing is not performed and the printing is stopped. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and a management method for managing the remaining number of printable sheets based on the amount of remaining toner, and in particular, can manage the number of printable sheets with high accuracy with respect to the amount of remaining toner in a near-end state. The present invention relates to a printing apparatus and a calculation method.

  Generally, in a printing apparatus, image data of a print job having a predetermined format typified by PDL (Page Description Language) is subjected to image processing by a print controller, and the image data after image processing is printed on printing paper by a print engine. Print out with. The print engine transports the printing paper stored in the paper storage with a transporting roll, and draws image data on the transported printing paper. In this drawing process, the toner filled in the toner cartridge is sprayed onto the printing paper, and the sprayed toner is colored on the printing paper by a pressure bonding device or the like.

  The number of sheets that can be printed by the print output in this print engine depends on the remaining amount of toner stored in the cartridge in addition to the number of print sheets stored in the sheet storage, and originally when the remaining amount of toner runs out (toner The toner can be used without waste by replacing the toner when the toner is used up.

  However, if you try to use the toner until it runs out completely, “blurred printing” will begin to occur when the remaining capacity is below a certain remaining capacity, so the desired print result may not be obtained and you may have to reprint. is there. As a result, printing paper is wasted, so that the toner is not used until it is completely removed, but is generally replaced before faint printing occurs.

  There is a technique for confirming that the toner has reached a certain remaining capacity or less and notifying the user that it is time to replace the toner. By using this technique, the user can recognize the replacement time of the toner, and can avoid the failure of the print output due to the insufficient remaining capacity of the toner. The remaining capacity at this time is not usually a capacity that causes faint printing immediately, but is a capacity that can still be printed and output, so the user is in the toner replacement period. In many cases, the printer continues to be used in a state in which this is notified, and this may cause faint printing.

  As a background to this, since it is still possible to perform normal print output when it is notified that it is time to replace the toner, there is an intention to use the toner as much as possible.

Considering that normal printing output is possible even when the remaining toner capacity is below a certain level, it is possible to prevent printing unevenness and printing loss and to prompt the user to replace the toner at the optimal timing. As the related art, there is one disclosed in Patent Document 1.
JP2002-131995

  In the technique disclosed in Patent Document 1, when printing is requested in a state where the toner is below a certain remaining capacity, the number of prints of the print data requested for printing is counted, and the number of prints is determined in advance. If the number is greater than or equal to the number, the user is prompted to replace the toner because there is no toner remaining to print out the print data. That is, it is determined whether or not the print data can be printed every time a print request is made. If all the print data cannot be printed, the printing itself is not performed.

  This is because there is a case where print output is not performed in spite of a state where normal print output is possible, and there is a problem that toner is wasted if the toner is replaced in this state. .

  Therefore, an object of the present invention is to provide a printing apparatus and a calculation method that can calculate the number of printable sheets with higher accuracy when the toner is below a certain remaining capacity.

  In order to achieve the above object, a first aspect of the present invention provides a toner amount detecting means for detecting a remaining toner amount of the toner in a printing apparatus that prints and outputs the toner filled in the toner cartridge on a printing paper. A near-end detection unit that detects a near-end state in which the residual toner amount detected by the toner amount detection unit is equal to or less than a predetermined toner amount, and the residual toner amount at the time when the near-end state is detected by the near-end detection unit. It is characterized by comprising a calculating means for calculating the number of prints that can be normally printed, and a print control means for controlling the print output within the range of the number of prints that can be normally printed calculated by the calculating means.

  The invention of claim 2 further comprises management means for managing a standard printable number of prints with the total toner amount of the toner cartridge in the invention of claim 1, wherein the calculation means is controlled by the near-end detection means. The number of printed sheets printed up to the near-end state from the amount of toner used until the near-end state is detected and the amount of toner per unit number used to print out the standard number of prints managed by the management unit And the number obtained by subtracting the number of printed sheets from the standard number of printed sheets managed by the managing unit is calculated as the number of printed sheets that can be printed normally.

  The invention of claim 3 further comprises counting means for counting the number of printed sheets in the invention of claim 1, wherein the calculating means uses the amount of toner used for the number of printed sheets counted by the counting means. Based on this ratio, the number of prints that can be normally printed with the remaining toner amount is calculated.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the print control unit increases or decreases the number of printed sheets calculated by the calculating unit based on a printing condition, and the increased or decreased number of printed sheets. It is characterized by being printed out within the range.

  According to a fifth aspect of the present invention, in the calculation method for calculating the number of sheets that can be printed normally based on the amount of remaining toner filled in the toner cartridge, the amount of remaining toner in the toner is detected by a toner amount detecting means, The near-end detection unit detects a near-end state in which the remaining toner amount detected by the toner amount detection unit is equal to or less than a predetermined toner amount, and the normal amount is determined by the remaining toner amount at the time when the near-end state is detected by the near-end detection unit. The number of printable prints is calculated.

  According to the present invention, after the near end is detected, the number of prints guaranteed to be printed is calculated based on the information of the print density per one sheet, the amount of toner used, and the print history, and the number of prints calculated using any one of the information is calculated. Since the printing output is performed within the range, the printing error can be minimized and the toner can be used without waste.

  In addition, the running cost for consumables such as printing paper and toner can be reduced.

  Hereinafter, an embodiment of a printing apparatus and a calculation method according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is an apparatus configuration diagram configured by applying a printing apparatus and a calculation method according to the present invention.

  In FIG. 1, a printer 100 as a printing apparatus includes a near-end detection unit 101, a calculation unit 102, a count unit 103, a storage unit 104, a determination unit 105, a display unit 106, a print control unit 107, and a print engine 108. Then, print output is performed based on the amount of toner filled in the toner cartridge of the print engine 108. The printer 100 manages the number of printable sheets with different accuracy between when the toner is sufficiently filled with toner and when the toner is in a near-end state where the toner is below a certain remaining amount.

  That is, the number of prints that can be printed normally with no blur printing in the near-end state (“near-end state”) is calculated with high accuracy.

  First, a detection processing method for detecting the near-end state will be described with reference to FIG.

  FIG. 2 is a diagram illustrating a state where the toner cartridge provided in the print engine 108 is filled with toner, and the light emitting element 201 and the light receiving element 202 are installed on both the left and right sides of the toner cartridge. The light emitting element 201 is an element that emits laser light, and the light receiving element 202 is an element that receives the laser light emitted from the light emitting element 201, and is provided at a position where the laser light having straightness can be received. Yes.

  When the laser light emitted from the light emitting element 201 is received by the light receiving element 202, it is detected that the obstacle (toner) has disappeared on the orbit of the laser light and the near end state is detected. At this time, the laser light emitted from the light emitting element 201 is emitted in parallel with the surface of the toner, and when the light receiving element 202 receives a certain amount of laser light, it is detected as near-end.

  In FIG. 2, FIG. 2 (a) shows the state of the toner cartridge filled with a sufficient amount of toner. In this case, the laser light emitted from the light emitting element 201 is blocked by the toner on the orbit, The light receiving element 202 cannot receive the laser beam. On the other hand, FIG. 2B shows a state of the toner cartridge having a toner amount capable of receiving the laser light emitted from the light emitting element 201 by the light receiving element 202, and the laser light starts to be received by the light receiving element 202. The near end can be detected by receiving a certain amount of light by the light receiving element 202.

  Further, FIG. 2C shows a toner cartridge having a toner amount in which a certain number of sheets are printed out even after it is detected that the near-end state is detected, and it is not strange even if faint printing occurs.

  As described above, when the laser light emitted from the light emitting element 201 is received by the light receiving element 202 over a certain amount, it is detected that the near end state is reached.

  In addition to the method of detecting the near end using the light receiving element 201 and the light emitting element 202, a configuration in which the near end state is detected by measuring the amount of electric resistance generated based on the toner amount may be employed. .

  Next, the operation content of the printer 100 in the near-end state detected by the method as described above will be described.

  When the near-end state is detected by the near-end detection unit 101 by monitoring the toner cartridge every certain time or constantly, the calculation unit 102 and the count unit 103 are notified that the amount of charged toner is in the near-end state. The calculation unit 102 performs a process of calculating the number of printed sheets (PV: PrintVolume) (hereinafter referred to as “PV number”) that guarantees normal printing in the near-end state, and stores the calculated PV number in the storage unit 104. This PV number indicates the number of sheets that can be printed out in the same printing state as before the near end is detected, that is, normal printing can be performed without causing faint printing due to lack of toner. The number is shown. In addition, when the near-end state is notified from the near-end detection unit 101, the count unit 103 updates the detection flag indicating the presence or absence of the near-end state to “ON” and stores it in the storage unit 104.

  Further, the counting unit 103 includes a counter, counts the number of printed sheets printed by the print engine 108, and stores the counted number in the storage unit 104. This count number is updated to “0 (zero)” when the toner cartridge of the print engine is replaced, and is again counted again.

  Below, the calculation method of the number of PV performed by the calculation part 102 is demonstrated.

  As a first calculation method, a method for calculating the number of PV based on a printing ratio (hereinafter referred to as “print density”) with respect to the entire printed document will be described.

  In this method, first, the total toner amount mounted on the toner cartridge is set to “Y”, and the remaining toner amount at the near end detection is set to “x”. In this case, the remaining toner amount “x” is a predetermined ratio with respect to the total toner amount “Y”. For example, when the near end is 20% or less of the total toner amount “Y”, the near end detection time is The remaining toner amount “x” is obtained as “Y × 0.2”.

  In addition, the number of PVs guaranteed to be printed with respect to the residual toner amount “x” at the time of near-end detection depends on the paper size and the print density. This print density is the print density “ The printing ratio is calculated as “100%”. At this time, if the amount of toner used when printing at a printing density of “100%” is “y”, the amount of toner used when printing at a printing density of “k%” is obtained as “y × (k / 100)”. be able to. This used toner amount “y” is a toner amount consumed when printing is performed at a printing density “100%”, and is a value determined in advance for each paper size.

  Thus, the number of PVs (PV100) for which printing is guaranteed when printing is performed at a printing density of “100%” can be calculated by the following (Formula 1).

PV100 = x / y (Formula 1)
Further, the number of PVs (PV_k) for which printing is guaranteed when printing is performed at a printing density “k%” can be calculated by the following (Formula 2).

PV_k = x / (y * (k / 100)) (Formula 2)
Incidentally, the print density “0%” indicates a case where printing is performed in a blank state, but the print density “0%” is excluded because it is equivalent to not printing output. As a result, the print density is in the range of “0 <k <= 100”.

  From the above, the PV number after near-end detection is calculated by setting the optimum printing density “k” according to the printing environment.

  The print density “k” is relatively higher in an environment in which image data including a lot of photographs and pictures is frequently printed out than in an environment in which image data composed of character data is frequently printed out. This print density “k” can be calculated from a statistically calculated value or a past actual value in the same environment.

  Next, as a second calculation method, a method for calculating the number of PV when the number of printable sheets is designated in advance with respect to the total amount of unused toner will be described.

  In this method, first, the total toner amount packed in the toner cartridge is “Y”, the standard toner usage amount used when a standard image is printed on the printing paper is “A”, and this standard toner usage amount is When “A” is printed out for the total toner amount “Y”, the standard number of printed sheets is “n”. Also, the near-end toner usage rate with respect to the total toner amount “Y” is set to “a”, and when this toner usage rate “a” is reached, it is detected that the toner is near-end.

  The standard number of prints “n” at this time is the number of prints that can be printed when the standard toner usage amount “A” is printed. For example, a general toner cartridge can output about 5000 sheets. Therefore, a large-capacity toner cartridge can print out about 8000 sheets. As described above, the standard print number “n” is a predetermined value.

  Further, since the near end is detected based on the usage ratio “a” of the toner used with respect to the total toner amount “Y”, for example, when the toner is used at 80% with respect to the total toner amount “Y”, In this case, the toner usage rate “a” is indicated as “0.8”.

  Then, the number of printed sheets (Pout) at the time when the near-end toner usage ratio “a” is reached can be calculated by the following (Equation 3).

Pout = (Y × a) / A (Formula 3)
This (Expression 3) is an expression showing the number of printed sheets (Pout) printed out by printing the toner capacity (Y × a) used at the near end time with the standard toner usage amount “A”, The number of printed sheets that have already been printed is calculated.

  Therefore, the number of PV (PV) for which printing is guaranteed based on the toner usage ratio “a” at the near end time can be calculated by the following (formula 4).

PV = n−Pout = n − ((Y × a) / A) (Formula 4)
The toner usage ratio “a” also falls within the range of “0 <a <= 1”.

  By using such a calculation method, it is possible to calculate the remaining number of PV when the standard toner usage amount “A” is printed out from the standard number of printed sheets.

  Incidentally, the standard toner usage amount “A” may be calculated from the total toner amount “Y” required for printing out the standard printing number “n”. In this case, the standard toner usage amount “A” "Can be obtained as" A = Y / n ".

  By applying this formula to (Formula 4), the PV number can be calculated by (Formula 5) shown below.

PV = n × (1−a) (Formula 5)
This is the number of sheets that can be printed only for the ratio of the remaining toner amount to the total toner amount in the standard print number.

  As a third calculation method, a method of calculating the number of PV by estimating the number of printed sheets from the number of printed sheets with respect to the amount of used toner will be shown.

  In this method, first, the total toner amount packed in the toner cartridge is set to “Y”, the number of printed sheets counted by a counter or the like is set to “PV0”, and the toner that is near-end with respect to the total toner amount “Y” is set. The usage rate is “a”.

  In this case, the toner amount “b” used to print out the printed number “PV0” that has already been printed out can be calculated by the following (formula 6).

b = PV0 / (Y × a) (Formula 6)
Therefore, the number of printable sheets (PV) after near-end detection can be calculated by the following (Formula 7).

PV = b * Y (1-a) = (PV0 / (Y * a)) * Y (1-a) (Formula 7)
By using such a calculation method, the remaining number of printable sheets can be calculated based on the state of the past print history for each use environment.

  The safety coefficient “s” may be multiplied to the arithmetic expressions (Expression 4) and (Expression 7) for calculating the number of PV by the second method and the third method. With this safety factor “s”, it is possible to calculate the optimum number of PV more suited to the use environment.

  The PV number calculated by the calculation method as described above is stored in the storage unit 104.

  The storage unit 104 stores the number of PV calculated by the calculation unit 102 when in the near-end state, and also stores the state of the detection flag set by the count unit 103. Further, the number of printed pages counted by the counting unit 103 is stored.

  Then, by subtracting and updating the number of printed sheets counted by the counter from the number of PV stored in the storage unit 104, the updated number of PV becomes the number of printed sheets guaranteed to be printed at the next print output.

  When the printer 100 receives a print request from a client terminal or the like, the determination unit 105 determines whether the number of print jobs output in response to the print request is equal to or less than the number of PVs. As a result of the determination, if the number of output sheets is equal to or less than the number of PV, the print control unit 107 is instructed to print out the print job because it is within the guaranteed range of printing. On the other hand, if the output number of the print job requested for printing exceeds the number of PVs, the print control unit 107 is instructed to stop the print output because printing cannot be guaranteed for all pages.

  At this time, the print control unit 107 performs print control based on the determination result in the determination unit 105. First, when the number of output print jobs requested to be printed is equal to or less than the number of PV, the print job is transferred to the print engine 108 and printed out. Next, if the number of output print jobs requested for printing exceeds the number of PV, the print job is discarded and print output is stopped. Then, the display unit 106 displays that print output has been stopped.

  In other words, this indicates that printing is performed only when all pages of the print job requested for printing can be printed out, and printing output is stopped when the number of printed pages exceeds the number of PV stored in the storage unit 104. For example, if the print request is a print job consisting of 100 pages and the number of PVs stored is “5”, printing is guaranteed for the first five pages. However, the remaining 95 pages are not guaranteed, and reprinting may have to be performed, thereby preventing unnecessary print output from occurring.

  Of course, the number of prints that can be guaranteed for printing, that is, the first five pages in the above example may be printed out, and printing may be stopped without printing out the remaining pages. These can be selected and set in advance.

  The print engine 108 is provided with a toner cartridge, and performs printing output by coloring the toner printing paper filled in the toner cartridge based on the print job. The print engine 108 is also provided with a toner cartridge replacement detection device. When the replacement detection device detects that the toner cartridge has been replaced with another toner cartridge, the count unit 103 is informed. In response to this notification, the count unit 103 updates the number of printed pages stored in the storage unit 104 to “0 (zero)”.

  In this replacement detection device, the identification number assigned to the toner cartridge is stored, and the replacement is detected by detecting the attachment of the toner cartridge assigned with a different identification number.

  With such a configuration, in the printer 100 of the present invention, it is possible to control print output based on information on the number of prints guaranteed to be printed in the near-end state calculated by the calculation unit 102.

  Note that the number of output sheets to be subtracted from the number of PVs can be calculated based on the printing conditions of the print job requested to be printed, and the number of output sheets to be subtracted is calculated based on each printing condition below.

  First, when double-sided printing is specified in the printing conditions set in the print settings, the total number of pages specified in the print job is divided by 2, and the number of pages with the decimal point raised is calculated as the number of print job outputs. For example, when all the pages specified in the print job are 7 pages, 4 pages obtained by rounding up the decimal point of “3.5” obtained by dividing “7” by 2 are calculated as the number of output sheets.

  In addition, when N-up printing for printing N pages per sheet of printing paper is specified, the total number of pages specified in the print job is divided by N, and the number of pages with the decimal point raised is the output page of the print job. Calculate with numbers. For example, when 4-up printing is specified and all pages specified in the print job are 13 pages, the decimal point of the value “3.5” obtained by dividing “14” by 4 is raised and 4 pages are set as the number of output sheets. calculate.

  In addition, when print output in the toner save mode with the toner density lighter than normal print output is specified, the total number of pages is multiplied by a predetermined ratio and the number of pages with the decimal point raised is the number of print job outputs. And calculate. For example, if all the pages specified in the print job are 10 pages and the toner use ratio in the toner save mode is 0.7, 7 pages obtained by multiplying 10 by 0.7 are used as the number of print job outputs. calculate.

  If a jam occurs in the printer in addition to the print conditions, the total number of pages specified in the print job or the number of output pages calculated under the above print conditions is added to the one page where the jam occurred to output the number of print jobs. And calculate.

  By subtracting the number of output sheets calculated in this way from the PV number, the remaining PV number for guaranteeing printing can be calculated.

  FIG. 3 is a diagram showing a flow of processing for printing out by limiting the number of printed sheets after the near-end detection in the printing apparatus of the present invention.

  In FIG. 3, the processing procedure differs depending on whether the amount of toner filled in the toner cartridge is in a predetermined near-end state. Therefore, when a print request is made, first, the near-end state is checked to confirm whether the toner end state is in the near-end state. A detection flag indicating whether or not it has been detected is confirmed (301).

  Next, it is determined by this flag confirmation processing whether the detection flag is “ON” (302). If the detection flag is not “ON” but “OFF” and the near-end state of the toner cartridge has not been confirmed ( If NO in 302), a process for confirming whether the toner amount is in the near-end state is performed thereafter.

  The flow of processing when the image data requested to be printed is not in the near-end state when printed out will be described below.

  First, the remaining toner capacity is detected (303), and it is determined from the remaining toner amount whether the toner is in a near-end state (304). If the near end is not detected by this detection process (NO in 304), a process for printing out the image data requested to be printed is performed (310). On the other hand, when the near end is detected (YES in 304), the detection flag is set to “ON” (305), and a process of calculating the number of prints (PV number) that guarantees printing in the near end state is performed ( 306).

  In this PV number calculation process, there are three calculation methods as calculated by the calculation unit of the apparatus configuration diagram shown in FIG. 1, and the PV number calculated using any one of the methods is stored (307).

  Then, the number of printed sheets requested for printing is counted (308), and it is determined whether the calculated number of PV is larger than the counted number of printed sheets (309). That is, if the counted number of printed sheets is equal to or less than the number of PVs, it is possible to guarantee printing of all pages of the print job. . Therefore, if the number of PV is equal to or greater than the counted number of printed sheets (YES in 309), print output is performed (310).

  If the number of PV is smaller than the counted number of printed sheets (NO in 309), the fact that the print output cannot be continued is displayed on the display (311), and the process of stopping the print output is performed (312).

  Next, processing when the detection flag indicating whether or not the near end state is in the “ON” state and the near end state of the toner cartridge has already been confirmed will be described.

  When the detection flag is “ON” indicating the near end state (YES in 302), the number of print requests received in the state where the near end is detected is counted (308). It is determined whether the counted number of printed sheets is equal to or less than the number of PVs already stored (309). If the number of printed sheets is equal to or less than the number of PVs (YES in 309), the number of printed sheets is output (310). If the number is less than or equal to the calculated number of PV (NO in 309), the fact that the print output cannot be continued is displayed on the display (311), and the print output process is stopped (312).

  As a result, printing is performed only when all pages of the print job requested to be printed can be guaranteed, and when all pages cannot be guaranteed printing, printing is not stopped and the occurrence of faint printing is prevented. it can.

  With the above processing, the printing apparatus of the present invention can calculate the number of prints for which printing is guaranteed from the amount of residual toner at the time of near-end detection.

  As a result, it is possible to calculate the number of prints that guarantees printing more accurately and with higher accuracy than the number of printable sheets for the unused toner capacity for print output, so that toner can be used without waste and printing errors can be minimized. It becomes possible to do.

  Therefore, by applying the present invention, it is possible to expect the effect that it is possible to prevent the stop of print output due to running out of toner, and it is possible to expect the effect that the running cost can be reduced because the toner can be used without waste.

  The present invention is not limited to the embodiments described above and shown in the drawings, and can be implemented with appropriate modifications within a range not changing the gist thereof.

  For example, the present invention can be applied to a case where a print job composed of a plurality of colors is printed out.

  The number of PV is calculated for each color forming a color space such as CMYK, and the printing is guaranteed by comparing the number of PV of the color having the smallest value among the color schemes used at the time of print output with the number of output requested by the print job. It can also be configured to determine whether printing output is possible.

  INDUSTRIAL APPLICABILITY The present invention is applicable to a printing apparatus that performs efficient print output using residual toner, and is particularly useful for preventing wasteful print output by calculating the number of prints that guarantees printing after near-end detection. It is.

1 is a configuration diagram of an apparatus configured by applying a printing apparatus and a calculation method according to the present invention. FIG. 5 is a diagram illustrating a state where toner is filled in a toner cartridge. The figure which shows the flow of the process which restrict | limits the number of prints after the near end detection in the printing apparatus of this invention, and prints it out.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Printer 101 Near end detection part 102 Calculation part 103 Count part 104 Storage part 105 Judgment part 106 Display part 107 Print control part 108 Print engine

Claims (5)

In a printing apparatus that prints out the toner filled in the toner cartridge by printing on the printing paper,
A toner amount detecting means for detecting a residual toner amount of the toner;
A near-end detection unit that detects a near-end state in which a residual toner amount detected by the toner amount detection unit is equal to or less than a predetermined toner amount;
Calculation means for calculating the number of prints that can be normally printed by the amount of residual toner at the time when the near-end state is detected by the near-end detection means;
A printing apparatus comprising: a printing control unit that controls printing output within a range of the number of printed sheets that can be printed normally by the calculation unit. Management means for managing a standard printable number of prints based on the total amount of toner in the toner cartridge;
The calculating means includes
Printing from the amount of toner used until the near-end state is detected by the near-end detection unit and the amount of toner per unit number used to print out the standard number of prints managed by the management unit to the near-end state 2. The printing according to claim 1, wherein the printed number of printed sheets is calculated, and a number obtained by subtracting the number of printed sheets from the standard number of printed sheets managed by the management unit is calculated as a number of printed sheets that can be printed normally. apparatus. A counting means for counting the number of printed sheets;
The calculating means includes
2. The printing apparatus according to claim 1, wherein the number of printed sheets that can be normally printed with the remaining toner amount is calculated based on a ratio of a used toner amount to a printed number of sheets counted by the counting unit. The print control means includes
The printing apparatus according to any one of claims 1 to 3, wherein the number of printed sheets calculated by the calculating unit is increased or decreased based on a printing condition, and printing is performed within the range of the increased or decreased number of printed sheets. In a calculation method for calculating the number of sheets that can be printed normally based on the amount of toner remaining in the toner cartridge,
A residual toner amount of the toner is detected by a toner amount detector;
A near-end detection unit that detects a near-end state in which a residual toner amount detected by the toner amount detection unit is equal to or less than a predetermined toner amount;
A calculation method comprising: calculating the number of prints that can be normally printed based on the amount of residual toner at the time when the near-end state is detected by the near-end detection unit.

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