Image forming device

Abstract

To provide a technique capable of reducing print processing time.SOLUTION: In an image-forming device, multiple second recording materials are conveyed at a first speed and the following first recording materials are conveyed at a first speed when the number of times when the second recording materials continue is less than a first threshold, and multiple second recording materials are conveyed at a second speed slower than the first speed when the number of times when the second recording materials continue is equal to or more than the first threshold in continuous fixing operation that continuously performs a heat-fixing process to multiple recording materials in a fixing section, and continuously performs a heat-fixing process to multiple second recording materials having a second width in which width orthogonal to a conveyance direction is narrower than the first width before performing a heat-fixing process of the first recording materials in which the width orthogonal to a conveyance direction is the first width.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus capable of switching an image forming speed. [Background technology]

[0002] An electrophotographic image forming apparatus that transfers a toner image onto a recording material and heat-fixes the toner image to form an image on the recording material may continuously form images on multiple recording materials. The conveyance of the multiple recording materials is controlled at a predetermined interval and a predetermined speed, and the recording materials are subjected to a heat-fixing process. When forming an image on a narrow piece of paper that is perpendicular to the conveyance direction as the recording material, the image may be formed at a process speed (second speed) slower than the fastest process speed (first speed) from the viewpoint of temperature rise in non-paper passing portions.

[0003] Patent Document 1 discloses a technique for shortening processing time during continuous printing of narrow recording materials by controlling the sheets to pass at a first speed instead of a second speed if the number of sheets of recording material is within a predetermined number. Patent Document 2 discloses a technique for executing a print job at the second speed if the first speed is specified in a certain print job but the immediately preceding print job specifies the second speed and the processing time is shortened even when downtime due to speed switching is taken into account. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-33713 A [Patent Document 2] JP 2012-245649 A Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a technique capable of shortening the print processing time. [Means for solving the problem]

[0006] In order to achieve the above object, an image forming apparatus according to the present invention comprises: an image forming unit that forms a toner image on a recording material; a fixing section for heat-fixing the toner image onto the recording material; A control unit that controls the conveyance of the recording material; In an image forming apparatus comprising: In a continuous fixing operation in which a plurality of recording materials are continuously subjected to a heat fixing process in the fixing section, the continuous fixing operation includes a step of heat fixing a plurality of second recording materials having a second width narrower than the first width orthogonal to a conveying direction before heat fixing a first recording material having a first width, The control unit is When the number of consecutive second recording materials is less than a first threshold value, the second recording materials are conveyed at a first speed, and the subsequent first recording materials are conveyed at the first speed; When the number of consecutive second recording materials is equal to or greater than the first threshold value, the second recording materials are conveyed at a second speed slower than the first speed. death, the first threshold value is the number of consecutive second recording materials for which a predetermined cooling period must be provided before fixing the first recording materials when a plurality of the second recording materials are transported at the first speed and the subsequent first recording materials are transported at the first speed; The control unit is When the number of consecutive second recording materials is equal to or greater than the first threshold value, the first recording material following the plurality of second recording materials conveyed at the second speed is conveyed at the second speed. The present invention is characterized by 。 Effect of the Invention

[0007] According to the present invention, the throughput can be further improved. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view of a main part of an image forming apparatus according to a first embodiment of the present invention; [Diagram 2] 1 is a cross-sectional view of a main part of a fixing device according to a first embodiment of the present invention; [Diagram 3] FIG. 1 is a diagram for explaining a configuration of a heater in the first embodiment. [Figure 4] Table of print contents and print jobs by patient [Diagram 5] Chart printed by Patient A using Example 1 [Figure 6] Chart printed by Patient B using Example 1 [Figure 7] Chart obtained by applying Comparative Example 1 to Patient A's printout [Figure 8] Chart obtained by applying Comparative Example 2 to the printout of Patient B [Figure 9] A chart showing the medication information printed for patient C at the second speed [Figure 10] A chart showing the medication information printed for Patient C at first speed [Figure 11] Chart showing Patient A printed at first speed followed by Patient B printed [Figure 12] A chart showing Patient A printed at a second speed followed by Patient B printed at a second speed DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, with reference to the drawings, the mode for carrying out the present invention will be described in detail by way of example. The dimensions, materials, shapes, and relative positions of the components described in the embodiments should be appropriately changed depending on the configuration of the device to which the invention is applied and various conditions. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the present invention. The components described in the embodiments are merely examples, and are not intended to limit the scope of the present invention to only those.

[0010] Example 1 In this embodiment, as a specific example of a recording material, an image forming apparatus that sequentially prints a medicine envelope, a receipt, and a medicine information sheet (hereinafter, referred to as "medication information") in a pharmacy will be described as an example. Also, examples of image forming apparatuses that form images on recording materials using an electrophotographic method to which the present invention can be applied include copiers and printers, but here, the case where the present invention is applied to a laser beam printer will be described.

[0011] <Description of the device> FIG. 1 is a cross-sectional view showing an image forming apparatus having an image forming section and a fixing device F. Here, the image forming section in which an unfixed toner image is formed on the surface of a photosensitive drum 100 is The image forming apparatus according to the present embodiment includes a photosensitive drum 100, which is rotated clockwise by a motor (not shown). Cleaning means 101 is brought into contact with the surface of the photosensitive drum 100 to remove unnecessary toner.

[0012] Then, the surface of the photosensitive drum 100 is made to have a uniform potential by the charging means 102. An electrostatic latent image is formed on the surface of the photosensitive drum 100 by the scanner device 103. Then, an unfixed toner image corresponding to the electrostatic latent image is formed on the surface of the photosensitive drum 100 by the developing device 104.

[0013] Here, a recording material S1, which is a wide recording material, is conveyed by conveying means from a paper feed tray 105 in the direction of the arrow. The toner image formed on the photosensitive drum 100 is transferred to the recording material S1 at a nip formed between the recording material S and a transfer device 106 constituting a transfer section. This toner image is conveyed to a fixing device F while still adhering to the recording material S by electrostatic attraction. The toner image is then pressed and melted by the fixing device F to become a fixed image. Thereafter, the recording material S1 is discharged onto a paper discharge tray 107.

[0014] Here, the configuration up to the transfer of the toner image onto the recording material in the image forming apparatus according to this embodiment corresponds to the image forming section of the present invention. Also, the fixing device F that heats and fixes the unfixed toner image transferred onto the recording material corresponds to the fixing section of the present invention.

[0015] The image forming apparatus in this embodiment has three paper feed trays. That is, the image forming apparatus in this embodiment has two more paper feed trays 108 and 109 in addition to the paper feed tray 105, and narrow recording materials S2 and S3 are set in the paper feed tray 108 and the paper feed tray 109.

[0016] The recording material S1 is A4 size vertically fed plain paper (medication information), the recording material S2 is A5 size vertically fed envelope (medication bag), and the recording material S3 is A5 size vertically fed plain paper (receipt). Note that these types of recording materials are merely examples, and other sizes and types of recording materials may be combined.

[0017] The image forming apparatus also has a control unit 110 as a control means, which controls the image forming speed and the temperature control of the fixing device F. The control unit 110 receives print jobs from a host computer (not shown). An example of print job information is "1st page: medicine envelope, A5 width, 2nd page: receipt, A5 width, 3rd page: medicine information, A4 width." Note that the format of the print job information does not matter as long as the order and width are known.

[0018] In cases where the recording starts with a medicine envelope (recording material S2) or a receipt (recording material S3), which are narrow recording materials, the image forming speed is set according to the number of consecutive sheets of medicine envelopes or receipts (two sheets in the above example), and control unit 110 operates the image forming device. The image forming speed is operated at a first speed (fast speed) of 240 mm / sec and a second speed (slow speed) of 160 mm / sec. Note that in cases where the first sheet is a medicine envelope, which is a wide recording material, control unit 110 sets the image forming speed to the first speed (fast speed).

[0019] The fixing device F will be described with reference to Fig. 2. The fixing device F is composed of a fixing sleeve 200, which is a cylindrical film member, and a heater 201, which is disposed inside (in the internal space) of the fixing sleeve 200 and contacts the inner surface thereof. A metal plate may be disposed between the heater 201 and the fixing sleeve 200. The fixing device F also has a pressure roller 202, which faces the heater 201 via the fixing sleeve 200, contacts the outer circumferential surface of the fixing sleeve 200 so as to be pressed against the heater 201, and cooperates with the heater 201 to pinch the fixing sleeve 200 and form a fixing nip portion N.

[0020] Here, the heater 201 is held by a holding member 203. The holding member 203 is a fixing roller. It also has a guide function for guiding the rotation of the rib 200. The pressure roller 202 rotates counterclockwise by receiving power from a motor (not shown). As the pressure roller 202 rotates, the fixing sleeve 200 is also rotated in the direction of the arrow (clockwise).

[0021] A thermistor Th is provided on the inner surface of the fixing sleeve 200. The fixing device F is connected to a control unit 110. The control unit 110 calculates power according to the temperature detected by the thermistor Th and supplies the power from an external power source to a heater 201, thereby controlling the temperature of the fixing sleeve 200 to a set temperature. A recording material (e.g., S1) carrying a toner image is fixed in the nip portion N while being sandwiched and conveyed in the direction of the arrow.

[0022] In this embodiment, the set temperature is 180° C. as the first temperature in the case of the first speed (fast speed), and 168° C. as the second temperature in the case of the second speed (slow speed). The set temperature is low in the case of the second speed, which is a slow image forming speed, because the toner takes a long time to pass through the fixing device F, and therefore a sufficient amount of heat can be applied to the toner even at a low temperature.

[0023] 3 shows the relationship between the longitudinal direction of the heater 201 and the width of the recording material. The heater 201 is based on an alumina substrate 300. A power supply contact 301 and a heating resistor 302 are formed in series on the alumina substrate 300. In addition, a glass coating (not shown) is applied to the area other than the power supply contact 301. The heater 201 is provided with a heating resistor 302 having a longitudinal length corresponding to the width of the recording material having the maximum width perpendicular to the conveying direction of the recording material. In other words, since the heating resistor 302 is formed to the width of an A4 size paper for portrait feeding, the heater 201 generates heat to the A4 width by power supplied from an external power source.

[0024] When an A5-width medicine bag or receipt is sandwiched and transported through the nip portion N, heat is trapped in the non-paper-passing portion 303, which is not absorbed by the paper, causing a so-called non-paper-passing portion temperature rise. When an A4-width medicine sheet is sandwiched and transported through the nip portion N when the non-paper-passing portion 303 has reached a certain temperature, an image defect called hot offset occurs at the edge of the medicine sheet at the position of the non-paper-passing portion 303. The second speed (slow speed) with a lower set temperature is more advantageous for preventing the non-paper-passing portion temperature rise.

[0025] In the image forming device of this embodiment, when up to three medicine envelopes or receipts (narrow size paper) are printed in succession at a first speed (fast speed), and then a medicine information sheet (wide size paper) is printed in succession, hot offset occurs due to a rise in temperature in the non-paper passing area. If up to two sheets are printed in succession, hot offset does not occur. The number of sheets (threshold number) at which hot offset occurs in this embodiment is three. For this reason, the image forming device of this embodiment is characterized in that it starts printing at the first speed (fast speed) when the number of medicine envelopes or receipts (narrow size paper) passed in succession is less than the threshold number, that is, up to two sheets, and at the second speed (slow speed) when the number of sheets is three or more, that is, equal to or greater than the threshold number.

[0026] In addition, after printing three consecutive sheets of medicine envelopes or receipts (narrow-width paper) at the first speed (fast speed), a cooling time (downtime) of about 6 seconds is required to prevent hot offset from occurring on the medicine information sheet (wide-width paper). The above threshold number of sheets and cooling time were determined through experiments. These values ​​vary depending on the configuration of the image forming device and the image forming speed.

[0027] <Operation of this embodiment> In the image forming apparatus according to the present embodiment, in a continuous image forming operation in which images are continuously formed on a plurality of recording materials, the conveying speed of the recording materials is controlled so as to shorten the time required to complete the continuous image forming operation. In particular, the control is performed to shorten the time required to complete a continuous fixing operation in which a plurality of recording materials are continuously subjected to heat fixing processing in a fixing unit during the continuous image forming operation.

[0028] The control is performed so as to avoid the occurrence of a cooling period for suppressing a temperature rise in non-paper passing portions in a continuous fixing operation in which a plurality of second recording materials (narrow-width recording materials) having a second width narrower than the first width are continuously heated and fixed before a first recording material having a first width is heated and fixed. The cooling period is required when the second recording materials transported at a first speed (fast speed) are continuous, but is not required when the second recording materials are transported at a second speed slower than the first speed.

[0029] A first threshold value is set as the number of consecutive second recording materials (narrow recording materials) that require a cooling period to avoid a temperature rise in non-paper passing portions when transported at a first speed (fast speed). In a print job, if the number of consecutive second recording materials is less than the first threshold value, no cooling period occurs, so that the throughput can be improved by continuously processing the second recording materials at the first speed (fast speed). On the other hand, if the number of consecutive second recording materials is equal to or greater than the first threshold value, the continuous processing of the second recording materials is performed at the second speed (slow speed). Even if a switching operation of the transport speed of the recording materials is required in a flow in which a plurality of print jobs are consecutive, if the time required for the switching operation is shorter than the cooling period, the throughput can be improved as a whole series of image forming operations.

[0030] In addition, when a large amount of the second recording material is continuously used, the total processing time may be shortened by providing a cooling period. In such a case, the second recording material may be continuously processed at the first speed. That is, the conveying speed of the recording material may be controlled so as to further shorten the time required to complete the entire continuous fixing operation based on the processing time of the first recording material at the first speed (the time required to complete fixing), the processing time of the first recording material at the second speed, the number of continuous first recording materials, the processing time of the second recording material at the first speed, the processing time of the second recording material at the second speed, the number of continuous second recording materials, the length of the cooling period, and the length of the switching time.

[0031] In addition, the first recording material is typically a wide recording material having the maximum width that can pass through the fixing section, but it does not have to be the maximum width recording material. In other words, the control of the present invention may be applied to a recording material that is wider than the second recording material and is less affected by the temperature rise in the non-paper passing portion than the second recording material as the first recording material.

[0032] The print contents for patients A and B are shown in Fig. 4(a). An example of the operation when printing a medicine envelope, receipt, and medicine information in that order will be described. Note that Fig. 4(b) shows print job information, with paper sizes listed in order starting from the first page. The control unit 110 refers to how many consecutive narrow sheets of paper (A5 portrait in this embodiment) are printed from the first sheet, and judges whether the number is below a threshold number.

[0033] In the case of Patient A, the narrow sheets of paper following the first one are a medicine envelope and a receipt, which are A5 size, making a total of two sheets, which is less than the threshold number. Therefore, image formation for Patient A's print job starts at the first speed (fast speed).

[0034] FIG. 5 shows a time chart for Patient A's print job, with time on the horizontal axis and the number of printed sheets on the vertical axis. The thick line in the chart indicates the time period during which the paper is fixed at the first speed (fast speed). When the image forming apparatus of this embodiment operates at the first speed (fast speed), the preparation time required for the fixing process is 4 seconds. Processing time 501 indicates the fixing process time period for the medicine envelope (narrow size paper). Processing time 502 indicates the fixing process time period for the receipt (narrow size paper). Processing time 503 indicates the fixing process time period for the medicine information (wide size paper). The time from completion of the fixing process to completion of paper discharge for the medicine information (wide size paper) (paper discharge time) is 0.6 seconds, and the printing completion time 504 is 7.9 seconds.

[0035] In the case of Patient B, the narrow paper following the first sheet is a total of three sheets, including the A5 size medicine envelope and receipt, which is more than the threshold number. Therefore, for Patient B's print job, image formation is started at the second speed (slow speed), and the second speed (slow speed) is maintained until the medicine information (wide size paper). Print.

[0036] FIG. 6 shows a time chart for the print job of Patient B, with time on the horizontal axis and the number of printed sheets on the vertical axis. The thick white line in the chart indicates the time period during which the paper is fixed at the second speed (slow speed). When the image forming apparatus of this embodiment operates at the second speed (slow speed), the preparation time required for the fixing process is 5 seconds. Processing times 601 and 602 indicate the time period during which the medicine envelope (narrow size paper) is fixed. Processing time 603 indicates the time period during which the receipt (narrow size paper) is fixed. Processing time 604 indicates the time period during which the medicine information (wide size paper) is fixed. The paper ejection time from the completion of the fixing process of the medicine information (wide size paper) is 0.9 seconds, which is slower than the first speed, and the time 605 for printing completion is 12.3 seconds.

[0037] <Effects of this embodiment> The effects of this embodiment will be explained using Comparative Example 1 in which the print job for Patient A is performed at the second speed (slow speed) and Comparative Example 2 in which the print job for Patient B is performed at the first speed (fast speed).

[0038] 7 shows a time chart for the case where the print job for patient A is performed at the second speed (slow speed) (Comparative Example 1). Processing time 701 indicates the fixing process time for the medicine envelope (narrow size paper). Processing time 702 indicates the fixing process time for the receipt (narrow size paper). Processing time 703 indicates the fixing process time for the medicine information (wide size paper). Since the image formation speed is slower than the operation of this embodiment, the printing completion time 704 is 10.8 seconds, which is longer than the printing completion time 504 of 7.9 seconds.

[0039] FIG. 8 shows a time chart when the print job for patient B is performed at the first speed (fast speed). Processing times 801 and 802 indicate the fixing process time period for the medicine envelope (narrow size paper). Processing time 803 indicates the fixing process time period for the receipt (narrow size paper). Processing time 804 indicates the fixing process time period for the medicine information (wide size paper). In addition, because three sheets of A5 size (narrow size paper) were printed consecutively at the first speed (fast speed), a 5-second cooling operation (cooling time) was performed before processing time 803. When printing is performed at the first speed (fast speed), the time required for printing itself is short, but downtime for the cooling operation occurs, so the processing time is long, with the printing completion time 805 being 13.8 seconds and the printing completion time 605 being 12.3 seconds.

[0040] As described above, when narrow papers are printed first and then wide papers are printed next, the image formation speed is determined depending on whether the number of narrow papers is less than a threshold value, thereby improving throughput.

[0041] <Variation 1> In this embodiment, printing for one patient has been described as an example. However, the operation of the present invention can also be applied when printing for multiple patients is performed consecutively. Specifically, for example, following printing of the medication information of a previous patient, the subsequent patient's medication envelope and receipt (new narrow recording material) are printed in succession, and then the subsequent patient's medication information (new wide recording material) is further printed. In such a case, the same effect can be obtained by determining and executing the image formation speed depending on whether the number of consecutive sheets of medication information and receipts of the subsequent patient is less than a threshold number.

[0042] For example, in the case where printing is performed consecutively for patient A and patient B, after printing for patient A is performed at a first speed, printing for patient B is switched to a second speed and image formation is performed. In this case, the same throughput improvement effect as described in this embodiment can be obtained in printing for patient B following printing for patient A.

[0043] <Variation 2> The print job information in this embodiment includes the order and the paper size of the recording material for each order, and when image formation starts, the control unit 110 determines the image formation speed based on the information up to the completion of printing. However, even if all information up to the completion of printing is not available, the format of the information may be different. For example, the image formation speed may be determined from the range of information obtained at the start of the printing operation. The print job information may also be in a format in which the number of sheets for each recording material is arranged in order, such as "First: 3 sheets of recording material S1, Next: 2 sheets of recording material S1, Next: 2 sheets of recording material S1". The effects of the present invention are not limited to the print job information in this embodiment.

[0044] <Modification 3> In this embodiment, an image forming apparatus installed in a pharmacy that prints A5 size medicine envelopes, A5 size receipts, and A4 size medicine information has been described as an example. However, the scope of application of the present invention is not limited to the paper sizes and recording material types shown in this embodiment. Even in office printing using plain paper of different paper sizes, the same effect can be obtained even if the size combination is different from that in the embodiment.

[0045] <Variation 4> In this embodiment, a fixing device having a heating resistor with an A4 vertical feed width and a wide recording material with an A4 vertical feed size are described as an example. However, the effect of the present invention is not limited to the relationship between the length of the heating element and the wide recording material in this embodiment. For example, the same effect can be obtained by using a heating resistor with an LTR size vertical feed width and a recording material with an A4 size vertical feed width as the wide recording material. Note that for an image forming device that can switch between multiple heat generating areas in the longitudinal direction, it is more effective to define wide and narrow recording materials separately for each heat generating area.

[0046] <Other> Further, examples of image heating devices to which the present invention can be applied include not only the fixing device mounted on the image forming apparatus described above, but also gloss imparting devices that improve the glossiness of a toner image fixed on a recording material by reheating the toner image, etc. When the present invention is applied to such gloss imparting devices, etc., it is possible to shorten the processing time of the continuous heating operation in which a plurality of recording materials are continuously heated in the heating section.

[0047] Example 2 In this embodiment, an image forming device is described which prints a medicine bag and receipt (narrow-width paper) at a second speed (slow speed) and then determines the image formation speed of the medicine information (wide-width paper) based on the number of sheets of medicine information (wide-width paper) printed (number of sheets passed continuously).

[0048] <Description of the device> The configuration of the image forming apparatus in this embodiment is the same as that in embodiment 1. Description of matters common to embodiment 2 and embodiment 1 will be omitted.

[0049] In order to reduce downtime due to speed switching, in Example 1, the medicine information (wide size paper) was printed at the image formation speed at the start of printing, that is, at the second speed (slow speed). However, only in the case where image formation was started at the second speed (slow speed), if there were a large number of medicine information (wide size paper), it is expected that throughput would be improved by printing at the first speed (fast speed) even taking into account the switching time, if the number of sheets of medicine information (wide size paper) was large.

[0050] That is, when the first recording material follows after a plurality of consecutive second recording materials conveyed at the second speed, the conveying speed of the first recording material is controlled according to the number of consecutive first recording materials. For example, when the number of consecutive first recording materials is small, a time for the switching operation is provided. As a result, the processing time may become longer for the entire series of image forming operations. In such a case, it is expected that the processing time can be shortened by continuing to process the first recording material at the slow second speed. On the other hand, when the number of consecutive first recording materials reaches a certain number, the overall processing time may be shortened compared to continuing at the slow second speed, even if it takes time for the switching operation. Therefore, a second threshold is set as the number of consecutive first recording materials following the second recording material at the second speed to determine whether or not the conveying speed needs to be switched. If the number of consecutive first recording materials is less than the second threshold, the first recording material is conveyed at the second speed following the second recording material without performing the switching operation. If the number of consecutive first recording materials is equal to or greater than the second threshold, the overall processing time can be shortened by switching the conveying speed, so the conveying speed is switched to the first speed to convey the first recording material and perform the heat fixing process.

[0051] The image forming device in this embodiment is characterized in that it compares the case where the medicine information (wide size paper) is printed at a first speed (fast speed) with the case where the medicine information is printed at a second speed (slow speed), and selects the image forming speed that completes printing of the medicine information sooner. Note that the switching time required to switch from the second speed (slow speed) to the first speed (fast speed) is 2.0 seconds.

[0052] <Operation of this embodiment> An example of the operation when a medicine envelope (narrow size paper), a receipt (narrow size paper), and a medicine information sheet (wide size paper) are printed in this order for patient C shown in FIG. 4 will be described.

[0053] In the case of Patient C, the number of subsequent medicine envelopes and receipts (narrow-width paper) is three, which is greater than the threshold number, so image formation is started at the second speed (slow speed). At this time, the chart in which the subsequent medicine information (wide-width paper) is printed at the second speed (slow speed) is shown in Fig. 9, and the chart in which the speed is switched to the first speed (fast speed) is shown in Fig. 10.

[0054] Fig. 9 is a chart showing the fixing process of the medicine envelope at processing times 901 and 902, the receipt at processing time 903, and the medicine information at processing times 904 to 906 at the second speed, with the end of printing at time 907 being 16.4 seconds. On the other hand, Fig. 10 is a chart showing the fixing process of the medicine information at processing times 1001 to 1003 after the receipt processing time 903 and the switch to the first speed for 2 seconds, with the end of printing at time 1004 being 16.0 seconds. In this way, since printing is completed earlier at time 1004 when the speed is switched to the first speed, in this embodiment, printing of the medicine information (wide size paper) is performed at the first speed (fast speed) in the print job for patient C.

[0055] <Effects of this embodiment> In this embodiment, printing of the medication information (wide size paper) can be completed 0.4 seconds faster by switching to the first speed (faster speed) and printing rather than continuing to print at the second speed (slower speed).

[0056] As described above, in the case where image formation is started at the second speed (slower speed), by comparing printing on wide paper at the first speed (faster speed) with printing on wide paper at the second speed (slower speed), it is possible to achieve further reductions in processing time by selecting the image formation speed that completes printing of the medication information more quickly.

[0057] Example 3 In this embodiment, we will describe an image forming device that determines the image formation speed for a medicine bag (narrow width paper) based on the subsequent printing content when printing of medication information (wide width paper) continues after printing of another patient's information at a second speed (slow speed).

[0058] <Description of the device> The configuration of the image forming apparatus in this embodiment is the same as that in the second embodiment. Explanation of matters common to Example 2 will be omitted.

[0059] In the above embodiments, when printing a medicine envelope and receipt (narrow size paper) followed by a medicine information (wide size paper), the image formation speed of the medicine envelope (narrow size paper) was set depending on whether the number of consecutive sheets of the medicine envelope and receipt (narrow size paper) was less than the threshold number. This allows each printing for consecutive patients to be performed with optimal throughput. However, only in the case where a medicine information (wide size paper) is printed at the second speed (slow speed), and then a medicine envelope and receipt (new narrow recording material) and a medicine information (new wide recording material) that are less than the threshold number of sheets are printed, it is expected that the overall processing time will be shortened if the number of consecutive sheets is small by continuing to print at the second speed (slow speed) without switching to the first speed (fast speed).

[0060] That is, in this embodiment, when a continuous fixing operation in which a plurality of second recording materials are continuously subjected to a heat fixing process and then a first recording material is heated and fixed is regarded as one print job, and this print job is executed multiple times in succession, the conveying speed control is executed to shorten the processing time. When the first print job of the consecutive print jobs is completed by conveying the first recording material at the second speed in the first print job, and the number of consecutive second recording materials in the next second print job is less than a first threshold, the conveying speed of the second recording material in the second print job is selected. Specifically, the processing time (first time) in the case where the conveying speed is switched to the first speed and the second print job is executed is compared with the processing time (second time) in the case where the second print job is executed continuously at the second speed, and the speed at which the processing time is shortened is selected. A third threshold is set as the number of consecutive second recording materials in the second print job to determine whether or not the conveying speed needs to be switched. When the number of consecutive second recording materials in the second print job is less than a third threshold, the second recording material is conveyed at the second speed in the second print job following the first print job without performing a switching operation.When the number of consecutive second recording materials is equal to or greater than the third threshold, switching the conveying speed shortens the overall processing time, so the conveying speed is switched from the first print job to the first speed and the second print job is executed.

[0061] The image forming device in this embodiment is characterized in that in a case where the previous patient's medication information (wide size paper) is printed at the second speed (slow speed) and the subsequent patient's printing is less than the threshold number of sheets, the image forming device selects the speed that will complete printing faster by comparing the case where image forming is continued at the second speed (slow speed) with the case where it is switched to the first speed (fast speed).

[0062] <Operation of this embodiment> In the case where patient A prints after patient B in Figure 4, we will explain the operation when printing a medicine envelope (narrow size paper), a receipt (narrow size paper), and a medicine information (wide size paper) in that order.

[0063] For printing of patient B, the number of sheets of the medicine envelope and receipt (narrow size paper) is equal to or greater than the threshold value, so image formation starts at the second speed (faster). For printing of the following patient A, the number of sheets of the medicine envelope and receipt (narrow size paper) is less than the threshold value, so it is determined whether to continue at the second speed (slower speed) or to switch the speed.

[0064] Figures 11 and 12 show charts in which the time to complete printing of patient B's medication information is set to 0 seconds. Figure 11 is a chart when switching to the first speed (fast speed). Processing time 1101 shows the fixing process time period for the medication envelope (narrow size paper). Processing time 1102 shows the fixing process time period for the receipt (narrow size paper). Processing time 1103 shows the fixing process time period at the first speed for the medication information (wide size paper). The print completion time 1104 at this time is 6.0 seconds.

[0065] FIG. 12 is a chart showing the second speed (slow speed), and the processing time 1201 is the bag 12 shows the fixing process time period for the receipt (narrow size paper). Processing time 1202 shows the fixing process time period for the receipt (narrow size paper). Processing time 1203 shows the fixing process time period for the medication information (wide size paper) at the first speed. The print completion time 1204 at this time is 5.8 seconds, which is faster than when the speed is switched. Therefore, in this embodiment, printing for patient A is performed at the second speed (slow speed).

[0066] <Effects of this embodiment> In this embodiment, printing can be completed 0.2 seconds faster by keeping the printing speed at the second speed (slower speed) than by switching to the first speed (faster speed).

[0067] As described above, in a case where the previous patient's medication information (wide size paper) is printed at the second speed (slow speed) and the subsequent patient's printing is less than the threshold number of sheets, the overall processing time can be reduced by selecting the speed at which printing is completed more quickly compared to continuing image formation at the second speed (slow speed) or switching to the first speed (fast speed).

[0068] The disclosure of the embodiments of the present invention includes the following configurations. (Configuration 1) an image forming unit that forms a toner image on a recording material; a fixing section for heat-fixing the toner image onto the recording material; A control unit that controls the conveyance of the recording material; In an image forming apparatus comprising: In a continuous fixing operation in which a plurality of recording materials are continuously subjected to a heat fixing process in the fixing section, the continuous fixing operation includes a step of heat fixing a plurality of second recording materials having a second width narrower than the first width orthogonal to a conveying direction before heat fixing a first recording material having a first width, The control unit is When the number of consecutive second recording materials is less than a first threshold value, the second recording materials are conveyed at a first speed, and the subsequent first recording materials are conveyed at the first speed; An image forming apparatus characterized in that, when the number of consecutive second recording materials is equal to or greater than the first threshold value, the plurality of second recording materials are transported at a second speed slower than the first speed. (Configuration 2) The image forming apparatus described in configuration 1, characterized in that the first threshold value is the number of consecutive second recording materials that, when a plurality of the second recording materials are transported at the first speed and the subsequent first recording materials are transported at the first speed, require a predetermined cooling period before fixing the first recording materials. (Configuration 3) The control unit is The image forming apparatus according to configuration 1 or 2, characterized in that, when the number of consecutive second recording materials is equal to or greater than the first threshold value, the first recording material following the plurality of second recording materials transported at the second speed is transported at the second speed. (Configuration 4) The control unit is when the number of consecutive second recording materials is equal to or greater than the first threshold value and the number of consecutive subsequent first recording materials is less than a second threshold value, conveying the second recording materials at the second speed and conveying the first recording materials at the second speed; The image forming apparatus according to any one of configurations 1 to 3, characterized in that when the number of consecutive second recording materials is equal to or greater than the first threshold value and the number of consecutive subsequent first recording materials is equal to or greater than the second threshold value, the image forming apparatus transports a plurality of the second recording materials at the second speed and transports a plurality of the first recording materials at the first speed. (Configuration 5) The image forming apparatus described in configuration 4, characterized in that the second threshold value is the number of consecutive first recording materials such that, when a plurality of the second recording materials are transported at the second speed and a plurality of the first recording materials are transported at the first speed, a first time required to complete the continuous fixing operation is shorter than a second time required to complete the continuous fixing operation when a plurality of the second recording materials are transported at the second speed and a plurality of the first recording materials are transported at the second speed. (Configuration 6) 6. The image forming apparatus according to configuration 5, wherein the first time period includes a switching time required to switch the conveying speed of the recording material. (Configuration 7) In a case where a plurality of continuous fixing operations are performed in succession, in which a plurality of second recording materials are continuously subjected to a heat fixing process and then a first recording material is heat fixed, in a first continuous fixing operation among the continuous fixing operations, the first recording material is conveyed at the second speed to complete the first continuous fixing operation, and the number of continuous second recording materials in a next second continuous fixing operation is less than the first threshold value, The control unit is When the number of consecutive second recording materials in the second continuous fixing operation is less than a third threshold value, the second continuous fixing operation is performed while maintaining the conveying speed of the recording material at the second speed; The image forming apparatus according to any one of configurations 1 to 6, characterized in that when the number of consecutive second recording materials in the second continuous fixing operation is equal to or greater than the third threshold value, the conveying speed is switched to the first speed and the second continuous fixing operation is performed. (Configuration 8) The image forming apparatus according to configuration 7, characterized in that the third threshold value is the number of consecutive second recording materials in the second continuous fixing operation, such that when the conveying speed is switched to the first speed and the second continuous fixing operation is performed, a first time required to complete the second continuous fixing operation is shorter than a second time required to complete the second continuous fixing operation when the conveying speed is maintained at the second speed. (Configuration 9) 9. The image forming apparatus according to configuration 8, wherein the first time period includes a switching time required to switch the conveying speed of the recording material. (Configuration 10) an image forming unit that forms a toner image on a recording material; a fixing section for heat-fixing the toner image onto the recording material; A control unit that controls the conveyance of the recording material; Equipped with In the fixing unit, in a continuous fixing operation in which a plurality of recording materials are continuously subjected to a heat fixing process, when a plurality of recording materials are transported at a first speed and continuously subjected to a heat fixing process, if a predetermined number of narrow-width recording materials, each of which has a width perpendicular to the transport direction of the recording materials narrower than the maximum width that can pass through the fixing section, are consecutively produced, it is necessary to provide a predetermined cooling period before continuing the subsequent heat fixing process, When the conveying speed of the recording materials is switched between the first speed and a second speed slower than the first speed, a predetermined switching time is required. In the image forming apparatus configured as above, The control unit is an image forming apparatus comprising: an image forming unit that controls a conveying speed of the plurality of recording materials so that the cooling period is not provided during the continuous fixing operation and the time required for completing the continuous fixing operation is shortened; (Configuration 11) When the narrow recording material continues at the second speed, the cooling period does not need to be provided. 11. The image forming apparatus according to claim 10, (Configuration 12) The image forming apparatus according to any one of configurations 1 to 11, characterized in that the fixing section has a cylindrical film, a heater arranged in the internal space of the film, and a roller that contacts the outer surface of the film and cooperates with the heater to pinch the film and form a nip between the film and the roller, and that the toner image is heated by utilizing heat from the heater while transporting a recording material through the nip. [Explanation of symbols]

[0069] 501: A period during which the medicine envelope is fixed at the first speed; 502: A period during which the receipt is fixed at the first speed; 503: A period during which the medicine information is fixed at the first speed; 504: A time when printing is completed

Claims

1. an image forming unit that forms a toner image on a recording material; a fixing section for heat-fixing the toner image onto the recording material; A control unit that controls the conveyance of the recording material; In an image forming apparatus comprising: In a continuous fixing operation in which a plurality of recording materials are continuously subjected to a heat fixing process in the fixing section, the continuous fixing operation includes a step of heat fixing a plurality of second recording materials having a second width narrower than the first width orthogonal to a conveying direction before heat fixing a first recording material having a first width, The control unit is When the number of consecutive second recording materials is less than a first threshold value, the second recording materials are conveyed at a first speed, and the subsequent first recording materials are conveyed at the first speed; When the number of consecutive second recording materials is equal to or greater than the first threshold value, the second recording materials are conveyed at a second speed slower than the first speed; the first threshold value is the number of consecutive second recording materials for which a predetermined cooling period must be provided before fixing the first recording materials when a plurality of the second recording materials are transported at the first speed and the subsequent first recording materials are transported at the first speed; The control unit is An image forming apparatus characterized in that, when the number of consecutive second recording materials is equal to or greater than the first threshold value, the first recording material following the multiple second recording materials transported at the second speed is transported at the second speed.

2. An image forming unit that forms a toner image on a recording material; a fixing section for heat-fixing the toner image onto the recording material; A control unit that controls the conveyance of the recording material; In an image forming apparatus comprising: In a continuous fixing operation in which a plurality of recording materials are continuously subjected to a heat fixing process in the fixing section, the continuous fixing operation includes a step of heat fixing a plurality of second recording materials having a second width narrower than the first width orthogonal to a conveying direction before heat fixing a first recording material having a first width, The control unit is When the number of consecutive second recording materials is less than a first threshold value, the second recording materials are conveyed at a first speed, and the subsequent first recording materials are conveyed at the first speed; When the number of consecutive second recording materials is equal to or greater than the first threshold value, the second recording materials are conveyed at a second speed slower than the first speed; the first threshold value is the number of consecutive second recording materials for which a predetermined cooling period must be provided before fixing the first recording materials when a plurality of the second recording materials are transported at the first speed and the subsequent first recording materials are transported at the first speed; The control unit is when the number of consecutive second recording materials is equal to or greater than the first threshold value and the number of consecutive subsequent first recording materials is less than a second threshold value, conveying a plurality of second recording materials at the second speed and conveying a plurality of first recording materials at the second speed; An image forming apparatus characterized in that, when the number of consecutive second recording materials is equal to or greater than the first threshold value and the number of consecutive subsequent first recording materials is equal to or greater than the second threshold value, a plurality of the second recording materials are transported at the second speed and a plurality of the first recording materials are transported at the first speed.

3. The image forming apparatus according to claim 2, characterized in that the second threshold value is the number of consecutive first recording materials such that when a plurality of the second recording materials are transported at the second speed and a plurality of the first recording materials are transported at the first speed, a first time required to complete the continuous fixing operation is shorter than a second time required to complete the continuous fixing operation when a plurality of the second recording materials are transported at the second speed and a plurality of the first recording materials are transported at the second speed.

4. 4. The image forming apparatus according to claim 3, wherein the first time period includes a switching time required to switch a conveying speed of the recording material.

5. An image forming unit that forms a toner image on a recording material; a fixing section for heat-fixing the toner image onto the recording material; A control unit that controls the conveyance of the recording material; In an image forming apparatus comprising: In a continuous fixing operation in which a plurality of recording materials are continuously subjected to a heat fixing process in the fixing section, the continuous fixing operation includes a step of heat fixing a plurality of second recording materials having a second width narrower than the first width orthogonal to a conveying direction before heat fixing a first recording material having a first width, The control unit is When the number of consecutive second recording materials is less than a first threshold value, the second recording materials are conveyed at a first speed, and the subsequent first recording materials are conveyed at the first speed; When the number of consecutive second recording materials is equal to or greater than the first threshold value, the second recording materials are conveyed at a second speed slower than the first speed; the first threshold value is the number of consecutive second recording materials for which a predetermined cooling period must be provided before fixing the first recording materials when a plurality of the second recording materials are transported at the first speed and the subsequent first recording materials are transported at the first speed; In a case where a plurality of continuous fixing operations are performed in succession, in which a plurality of second recording materials are continuously subjected to a heat fixing process and then a first recording material is heat fixed, in a first continuous fixing operation among the continuous fixing operations, the first recording material is conveyed at the second speed to complete the first continuous fixing operation, and the number of continuous second recording materials in a next second continuous fixing operation is less than the first threshold value, The control unit is When the number of consecutive second recording materials in the second consecutive fixing operation is less than a third threshold value, In this case, the second continuous fixing operation is performed while maintaining the conveying speed of the recording material at the second speed, An image forming apparatus characterized in that, when the number of consecutive second recording materials in the second continuous fixing operation is equal to or greater than the third threshold value, the conveying speed is switched to the first speed and the second continuous fixing operation is performed.

6. The image forming apparatus according to claim 5, characterized in that the third threshold value is the number of consecutive second recording materials in the second continuous fixing operation, such that when the conveying speed is switched to the first speed and the second continuous fixing operation is performed, a first time required to complete the second continuous fixing operation is shorter than a second time required to complete the second continuous fixing operation when the conveying speed is maintained at the second speed.

7. 7. The image forming apparatus according to claim 6, wherein the first time period includes a switching time required to switch the conveying speed of the recording material.

8. 2. The image forming apparatus according to claim 1, wherein the fixing section has a cylindrical film, a heater disposed in the internal space of the film, and a roller that contacts the outer surface of the film and cooperates with the heater to pinch the film and form a nip between the film and the roller, and heats a toner image using heat from the heater while transporting a recording material through the nip.

Images