JP2021026228A - Image forming apparatus and image forming system - Google Patents

Abstract

To provide a technique capable of improving productivity regardless of the size of a recording material, and extending the life of an apparatus.SOLUTION: Among recording materials that can be conveyed at a nip part of a fixing unit, at least for a recording material having a width smaller than a recording material having the maximum width in a direction orthogonal to a conveyance direction, an image forming apparatus records the number of recording materials having the smaller width during continuous paper feed for continuously passing the recording materials through the nip part as a history per one continuous paper feed, in continuously feeding the recording materials having the smaller width, when a representative value of the number of the recording materials having the smaller width per one continuous paper feed acquired from the history is smaller than a predetermined threshold, executes a first operation mode for controlling the conveyance speed to a first speed, and when the representative value is equal to or larger than the threshold, executes a second operation mode for controlling the conveyance speed to a second speed slower than the first speed, with the conveyance interval between the recording materials during the continuous paper feed being the same as that in the first operation mode.SELECTED DRAWING: Figure 4

Description

The present invention relates to an image forming apparatus such as a copying machine such as an electrophotographic method and a printer that includes an image heating apparatus and forms an image on a recording material, and relates to an improvement in throughput of small-sized paper.

Conventionally, the following techniques have been proposed in order to suppress the temperature rise of the non-passing portion generated in the film fixing device used in the electrophotographic image forming apparatus to a desired value or less. For example, in Patent Document 1, the throughput (productivity) is changed according to the width of the recording material. When the width of the recording material is narrow, the throughput is lowered (the paper feed interval is widened) to control the temperature rise of the non-passing paper portion so as not to become excessive.
Further, for example, Patent Document 2 proposes an image forming apparatus that changes the image forming speed according to the width of the recording material, instead of changing the feeding interval and changing the throughput according to the width of the recording material. Patent Document 2 has two-speed image forming speeds (mm / sec) of 200 mm / sec and 100 mm / sec.
For wide recording materials such as A4, letter, and legal size (hereinafter referred to as large size paper), the space between papers (when continuously fed, the rear end of page N and the tip of page N + 1) Distance) is 65 mm. Then, the throughput is 33 sheets / minute for A4 size, 34.8 sheets / minute for letter size, and 28.5 sheets / minute for legal size. Here, the numerical value of 65 mm between papers means the minimum amount of paper that can be guaranteed by the variation in the paper feed timing, the variation in the response timing of the sensor in the transport path, and the like among the minimum sheets that the image forming apparatus can take. On the other hand, narrow recording materials (hereinafter referred to as small size paper) B5, A5, and exe size recording materials are set as one group, and the image formation speed is set to 100 mm / sec, which is half that of large size paper. , The throughput is controlled so that the space between papers is 65 mm. As a result, the throughput of B5, A5, and exe size is 18 sheets / minute. As a result, when the image forming speed is slow, the amount of heat required for fixing is small, so that by setting the temperature of the fixing film low, it is possible to suppress the temperature rise of the non-passing portion.
Further, for example, in Patent Document 3, when printing a small size paper in an image forming apparatus having a plurality of image forming speeds, it is proposed to control the image forming speed by switching the image forming speed according to the number of sheets to be printed. Has been done. In this case, when printing a small number of sheets, it is unlikely that the temperature rise of the non-passing portion exceeds a desired value, so printing is performed at the fastest image forming speed. On the other hand, when printing a large number of sheets, printing is performed at a slow image forming speed in order to suppress the temperature rise of the non-passing portion.

Japanese Unexamined Patent Publication No. 7-199694 Japanese Unexamined Patent Publication No. 2003-50519 Japanese Patent No. 5455493

However, in Patent Document 1, there is a difference in throughput between large size paper and small size paper. Due to the speeding up of the image forming apparatus, the throughput increases in proportion to the image forming speed only for large size paper, and the throughput does not improve for small size paper. Further, when the throughput is lowered, the space between papers is widened, so that the rotation time of the cartridge of the image forming unit is long and the life is shortened for printing a predetermined number of sheets. In addition, in order to cope with the temperature rise of the non-passing paper portion, it is necessary to widen the paper spacing from a small number of sheets to reduce the throughput, and the total productivity (average throughput) when a large number of sheets are printed becomes low.
Further, in Patent Document 2, the image forming speed is fixed by the width of the recording material, and the image forming speed is always slow in the small size paper, and the throughput is lowered. Therefore, the throughput is reduced even when printing a small number of sheets, which is less affected by the temperature rise of the non-passing paper portion.
Further, in Patent Document 3, the optimum image formation speed is selected according to the number of prints, but the number of prints is not always known when the operation of image formation is started. That is, in the case of a printer, the number of prints is determined after the image controller unit that converts the image information sent from the host computer into printable information has converted all the image information. Therefore, when the number of prints is large, if the number of prints is known, the time until the start of printing is extended, and the time until the first print is output (First Print Out Time: FPOT) is increased. Become slow. Therefore, if it is desired to speed up the FPOT, the image forming operation is started when the image controller unit processes the first image information, so that the number of subsequent prints is not always known.
Similarly, in the case of a copier, the image forming operation is started when the first sheet of paper is read by the image reading device, so it is known how many subsequent copies will be made. Not exclusively.

An object of the present invention is to provide a technique capable of improving productivity regardless of the size of a recording material and extending the life of the apparatus.

In order to achieve the above object, the image forming apparatus of the present invention
An image forming part that forms an image on the recording material,
A fixing portion having a nip portion for sandwiching and transporting the recording material and heating the image in the nip portion to fix the image to the recording material.
At least during continuous paper passing, the recording material having a width narrower than that of the recording material having the maximum width in the direction orthogonal to the transport direction among the recording materials that can be conveyed by the nip portion is continuously passed through the nip portion. A storage unit that stores the number of recording materials having a narrow width in the above as a history for each continuous paper passing.
A control unit that controls the transport speed of the recording material when passing through the nip unit,
In an image forming apparatus including
The control unit
When the narrow recording material is continuously passed through the paper,
When the representative value of the number of sheets of the narrow recording material acquired from the history in one continuous paper passing is smaller than a predetermined threshold value, the first transport speed is controlled to the first speed. Run the operating mode,
When the representative value is equal to or higher than the threshold value, the transport interval of the recording material during continuous paper passing is the same as that of the first operation mode, and the transport speed is slower than the first speed. It is characterized by executing a second operation mode controlled by.
In order to achieve the above object, the image forming system of the present invention
It has an image forming portion that forms an image on the recording material, a nip portion that sandwiches and conveys the recording material, and passes through the nip portion, a fixing portion that heats the image in the nip portion and fixes the image to the recording material, and the nip portion. An image forming apparatus including a control unit for controlling the transport speed of the recording material at the time of
It is connected to the image forming apparatus by a bidirectionally accessible network, and at least the width of the recording material that can be conveyed by the nip portion is larger than that of the recording material having the maximum width in the direction orthogonal to the conveying direction. A server including a storage unit that stores the number of recording materials having a narrow width at the time of continuous paper passing through the nip portion of a narrow recording material as a history for each continuous paper passing.
In an image forming system that has
The control unit
When the narrow recording material is continuously passed through the paper,
When the representative value of the number of sheets of the narrow recording material acquired from the history in one continuous paper passing is smaller than a predetermined threshold value, the first transport speed is controlled to the first speed. Run the operating mode,
When the representative value is equal to or higher than the threshold value, the transport interval of the recording material during continuous paper passing is the same as that of the first operation mode, and the transport speed is slower than the first speed. It is characterized by executing a second operation mode controlled by.

According to the present invention, the productivity can be improved regardless of the size of the recording material, and the life of the apparatus can be extended.

Schematic cross-sectional view of the image forming apparatus of Examples 1 and 2. Schematic cross-sectional view of the image heating apparatus of Examples 1, 2 and 3. The control block diagram of the first embodiment Control flowchart of the first embodiment Graph showing the throughput of Example 1 Graph showing the use case of Example 1 Control flowchart of the second embodiment Graph showing the throughput of Example 3 Graph showing the throughput of Example 3 Control flowchart of the third embodiment Schematic cross-sectional view of the image forming apparatus of Example 3 The control block diagram of the fourth embodiment The control block diagram of the fifth embodiment

Hereinafter, embodiments for carrying out the present invention will be described in detail exemplarily based on examples with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in this embodiment should be appropriately changed depending on the configuration of the apparatus to which the invention is applied and various conditions. That is, it is not intended to limit the scope of the present invention to the following embodiments.

[Example 1]
[Configuration of image forming apparatus]
FIG. 1 is an exemplary schematic configuration diagram of an electrophotographic image forming apparatus in this embodiment. Examples of the image forming apparatus to which the present invention can be applied include a copying machine and a printer using an electrophotographic method and an electrostatic recording method, and here, an image is formed on a recording material P by using an electrophotographic method. A case where it is applied to a laser printer will be described.

The video controller 120 receives and processes image information and print instructions transmitted from an external device such as a host computer. The control unit 113 is connected to the video controller 120, and controls each unit constituting the image forming apparatus in response to an instruction from the video controller 120. When the video controller 120 receives a print instruction from an external device, image formation is executed by the following operations.

The image forming apparatus 100 feeds the recording material P by the feeding roller 102 and conveys it toward the intermediate transfer body 103. The photosensitive drum 104 is rotationally driven in a counterclockwise direction at a predetermined speed, and is uniformly charged by the primary charger 105 in the rotational process. The laser beam modulated corresponding to the image signal is output from the laser beam scanner 106, and the photosensitive drum 104 is selectively scanned and exposed to form an electrostatic latent image. The developer 107 rotates and drives the developing roller 118 to attach powder toner, which is a developer, to the electrostatic latent image and visualize it as a toner image (developer image). The toner image formed on the photosensitive drum 104 is primarily transferred onto the intermediate transfer body 103 that rotates in contact with the photosensitive drum 104.

Here, the photosensitive drum 104, the primary charger 105, the laser beam scanner 106, the developer 107, and the developing roller 118 have four colors of cyan (C), magenta (M), yellow (Y), and black (K). Each is arranged. Then, the toner images for four colors are sequentially superimposed and transferred on the intermediate transfer body 103 in the same procedure. The toner image superimposed and transferred on the intermediate transfer body 103 is secondarily transferred onto the recording material P by the transfer bias applied to the transfer roller 108 in the secondary transfer portion formed by the intermediate transfer body 103 and the transfer roller 108. Will be done. After that, the fixing device (image heating device) 200 as the fixing unit (image heating unit) heats and pressurizes the recording material P to fix the toner image and discharge it to the outside of the machine as an image forming product.
In the above configuration, the configuration related to the formation of the unfixed toner image on the recording material corresponds to the image forming portion in the present invention.

The control unit 113 manages the transport status of the recording material P by the transport sensor 114, the resist sensor 115, the pre-fixing sensor 116, and the fixing paper discharge sensor 117 on the transport path of the recording material P. In addition, the control unit 113 has a storage unit that stores the temperature control program of the fixing device 200. The control circuit 400 as a heater driving means connected to the commercial AC power supply 401 supplies electric power to the fixing device 200. In this embodiment, an image forming apparatus having a maximum paper passing width of 216 mm in a direction (width direction) orthogonal to the transport direction of the recording material P is used, and a letter size (216 mm × 279 mm) recording material is printed. It is possible to do.

[Structure of fixing device (image heating device)]
FIG. 2 is a schematic cross-sectional view of the fixing device 200 in this embodiment. The fixing device 200 includes a fixing film 202 as an endless belt, a heater unit 310 that contacts the inner surface of the fixing film 202, a pressure roller 208 that contacts the outer surface of the fixing film 202, and a metal stay 204. The pressurizing roller 208 forms a fixing nip portion N together with the heater 300 via the fixing film 202. The heater unit 310 includes a heater 300 and a heater holding member 201 that holds the heater 300.

The fixing film 202 is a multi-layer heat-resistant film formed in a tubular shape, and a heat-resistant resin such as thin-walled polyimide or a metal such as stainless steel can be used as the base layer. Further, in order to prevent adhesion of toner and ensure separability from the recording material P on the surface of the fixing film 202, heat resistance such as tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA) having excellent releasability is obtained. A release layer is formed by coating with a resin. Further, particularly in an apparatus for forming a color image, a heat-resistant rubber such as silicone rubber may be formed as an elastic layer between the base layer and the release layer in order to improve the image quality.

The pressure roller 208 as a pressure member has a core metal 209 made of iron, aluminum or the like, and an elastic layer 210 made of silicone rubber or the like.

The heater 300 is a heater heated by a heating element provided on a ceramic substrate 305, and is provided on the opposite side of the fixing nip portion N and the surface protective layer 308 provided on the fixing nip portion N side. A surface protective layer 307 is provided. Power is supplied from an electrode (not shown) provided on the opposite side of the fixing nip portion N. Further, the thermistor 212 as an element (temperature detection unit) for detecting the temperature of the heater 300 is in contact with the heater 300. The heater 300 is held by the heater holding member 201 made of heat-resistant resin and heats the fixing film 202. The heater holding member 201 also has a guide function for guiding the rotation of the fixing film 202.

The metal stay 204 is fixed between the fixing film 202 and the pressure roller 208 by urging the heater holding member 201 holding the heater 300 toward the pressure roller 208 in response to a pressing force (not shown). The nip portion N is formed.

The pressurizing roller 208 receives power from the motor 30 and rotates in the direction of arrow R1. As the pressure roller 208 rotates, the fixing film 202 is driven to rotate in the direction of arrow R2. The unfixed toner image on the recording material P is fixed by applying heat to the fixing film 202 while sandwiching and transporting the recording material P in the fixing nip portion N.

[Control block configuration]
FIG. 3 shows a control block diagram in this embodiment. The video controller 120 receives and processes image information and print instructions transmitted from an external device 501 such as a host computer. Upon receiving the image information and the print instruction, the video controller 120 instructs the control unit 113 to perform a preparatory operation. After that, the video controller 120 converts the image information into printable information, and instructs the control unit 113 to perform an image forming operation.

In response to the instruction from the video controller 120, the image formation control unit 502 prepares according to the preparation operation 1 according to the preparation operation instruction before the image formation operation is instructed, and the print mode after the image formation operation is instructed. Operation 2, control the image formation operation. In the preparatory operation 1, the fixing device 200 and the laser beam scanner 106 are started to be driven. In the preparatory operation 2, a preparatory operation necessary for an image forming operation that is not performed in the preparatory operation 1 is performed. Specifically, in the preparatory operation 2, the driving of the photosensitive drum 104, the primary charger 105, the developing device 107, the intermediate transfer body 103, and the transfer roller 108 is started. The print mode is an image formation condition according to the type of recording material, and includes a transfer speed, a transfer condition, a target temperature for fixing, and the like.

The toner image control unit 503 controls the transfer bias of the laser 483, the scanner motor 473, the drum motor 475, the primary charger 477, the developing motor 479, the intermediate transfer motor 481, and the transfer roller 108 according to the image formation instruction of the image formation control unit 502. Toner image is formed.
The temperature control unit 505 determines the target temperature of the heater 300 controlled by the heating element control unit 507 according to the preparatory operation instruction and the image formation instruction of the image formation control unit 502.
The print operation history collection unit 506 stores the print operation history in the storage device (storage unit) 469.

Next, the print operation history will be described. The printing operation is started by the instruction from the video controller 120, and all the prints (a plurality of recording materials of a predetermined size are continuously passed through, and image formation / image fixing is continuously performed for each of the plurality of recording materials). One job is until the operation) is completed. Information on how many sheets have been printed continuously in this one job and paper size information are stored as a print operation history. An example is shown in Table 1. The history can store the latest 100 jobs.

(Table 1) Print operation history

Table 2 shows an example of the analysis result of the print operation history. The print operation history analysis unit 508 stores the analysis result of the print operation history in the storage device 469. In the print operation history analysis in this embodiment, the average value of the number of continuous prints per job for each paper size is calculated. For example, as the print operation history shown in Table 1, among the latest 100 jobs, there are 3 jobs having a paper size of A5. When the number of continuous prints for each job is 2, 4, or 6, respectively, the print operation history analysis result is stored in the storage device 469 as an average value of 4.

(Table 2) Print operation history analysis

In this embodiment, the average value of the number of continuous prints is used as the representative value of the analysis result, but not only the average value but also the median value, the mode value, and the standard deviation may be combined.

[Control method of image formation operation]
FIG. 4 is a control flowchart in this embodiment.
Upon receiving the image information and the print instruction transmitted from the external device 501 in S401, the video controller 120 starts the work of converting the image information into printable information. In addition, the control unit 113 is instructed to perform a preparatory operation.

The image formation control unit 502 included in the control unit 113 in S402 receives the preparatory operation instruction and determines whether or not the number of print jobs has been determined. For example, when the number of print jobs is only one, there is a possibility that the number of print jobs is fixed when the preparatory operation instruction is received. However, if the number of print jobs is large, it is highly possible that the number of print jobs has not been determined at this point.

If the number of print jobs is fixed in S402, the image formation control unit 502 receives the number of print jobs from the video controller 120 in S403.
In S404, the number of print jobs is compared with the number of predetermined image formation speed switching (hereinafter, speed switching number), and if the number of print jobs is smaller, printing is executed at the first image forming speed in S405. (First operation mode). On the other hand, when the number of print job sheets is larger than the predetermined speed switching number in S404 (when the speed switching number or more), printing is executed at the second image forming speed in S406 (second operation mode).

If the number of print jobs is not fixed in S402, the print operation history analysis unit 508 acquires the print operation history analysis result from the storage device 469 in S407.
In S408, when the average value of the number of continuous prints of the paper size specified in the print job is less than the predetermined speed switching number from the print operation history analysis result, printing is executed at the first image formation speed in S409. .. On the other hand, in S408, when the average value of the continuous print number history is larger than the predetermined speed switching number (when the speed switching number or more), printing is executed at the second image forming speed in S410. That is, when the representative value of the number of sheets in one continuous paper passing is equal to or more than a predetermined threshold value, the transport speed of the recording material is slowed down.

After printing all the print jobs in S411, the print operation history collection unit 506 stores the number of print jobs in the storage device 469 in S412.
In S413, the print operation history analysis unit 508 acquires the latest print operation history from the storage device 469, calculates the average value of the number of continuous prints for each paper size, and stores it in the storage device 469.

[Throughput comparison]
In the image forming apparatus of this embodiment, the first image forming speed is 200 mm / sec and the second image forming speed is 100 mm / sec. The maximum width of the recording material that can be printed is the width of the letter vertical feed (216 mm). The productivity when printing a B5 size recording material as a small size paper will be described with reference to this example and a comparative example.

FIG. 5A shows the number of continuous prints [pages] and the throughput (when the B5 size paper is passed at the first image formation speed (200 mm / sec) and the second image formation speed (100 mm / sec). It is a graph which shows the relationship of ppm (the number of prints per minute).

The fixing temperature at the first image forming speed (control target temperature that the detection temperature of the thermistor 212 should maintain) is about 200 ° C. in this embodiment from the viewpoint of fixing property. When the paper is passed at the first image forming speed, the paper starts at 37 ppm at first, and the temperature of the non-passing portion rises to near the heat resistant temperature of the fuser by raising the temperature of the non-passing portion at about 3 sheets. Therefore, the throughput, which is the number of recording materials passing through the fixing nip portion per unit time, is gradually reduced from 18 ppm to 5 ppm (the space between papers (transportation interval of recording materials) is widened).

On the other hand, the fixing temperature at the second image forming speed is about 150 ° C., which is lower than the fixing temperature setting at the first image forming speed because the image forming speed is slower than the first image forming speed. To do. Therefore, since the fixing temperature itself is low, the temperature rise of the non-passing portion is also low, and when the paper is passed at the second image forming speed, the paper starts to pass at an initial value of about 18.5 ppm, and then the temperature of the non-passing portion is reached. Never reaches near the heat resistant temperature of the fuser. Therefore, the throughput can be maintained at 18.5 ppm.

Next, when printing B5 size paper with an image forming apparatus installed on the market, the number of continuous prints varies depending on the user. In this embodiment, two types of use cases are assumed. FIG. 6A shows the ratio of each number of prints to all jobs as use case 1. For example, the ratio of one print is 25% of all jobs. When the number of printed sheets is 11 or more, one section is set, and the ratio is 4%. Next, as the second use case, use case 2 is shown in FIG. 6 (b). In use case 2, the tendency of the number of prints is different from that in use case 1, and it is assumed that the number of prints of 6 and 7 is the largest as a ratio. In addition, in the case of 11 or more sheets, one section is set and the ratio is 6%. That is, in this embodiment, when printing B5 size paper, it is assumed that one user uses it like use case 1 and another user uses it like use case 2. There is.

Next, in order to compare the throughput of B5 size paper, Comparative Example 1 will be described. As Comparative Example 1, the image forming speed is fixed at the first image forming speed (200 mm / sec), and the space between papers is widened in order to suppress the temperature rise of the non-passing portion. The throughput for each number of prints at this time is a graph of the solid line (200 mm / sec) in FIG. 5 (a). The time from the start to the end of printing for each number of prints is shown in Table 3, which is shown by the solid line in FIG. 5 (b).

(Table 3) Printing time at 200 mm / sec

Here, assuming that the user prints at the ratio of use case 1, for example, when the number of jobs is 100, one print has 25 jobs, two prints have 25 jobs, and similarly 3. There are 15 jobs for printing one sheet. When 100 jobs are printed in this use case 1, the total print time required is 1729 seconds from Table 4.

(Table 4) Use Case 1: Time required for 100 jobs (Comparative Example 1)

That is, since the number of jobs with one print is 25% in use case 1, it can be assumed that there are 25 jobs out of 100 jobs. Moreover, since the time required for printing one sheet is 6.6 seconds, it takes a total of 165 seconds. The same calculation can be performed when the number of prints is 2 or more, but the ratio of jobs with 11 or more prints is 4%, but as a method of calculating the print time, the representative value is 15 prints. Used as. The reason is that the median frequency of 11 or more jobs is assumed to be 15. Therefore, assuming use case 1 in Comparative Example 1, it takes 1729 seconds to process 100 print jobs.

Next, assuming that the user prints at the ratio of use case 2, when printing 100 jobs, the total print time required is 3109 seconds from Table 5.

(Table 5) Use case 2: Time required for 100 jobs (Comparative example 1)

Next, Comparative Example 2 will be described. In Comparative Example 2, the image formation speed is controlled to be switched for each paper size. When printing B5 size paper, the second image formation speed (100 mm / sec) is used. The throughput for each number of prints at this time is a graph of the broken line (100 mm / sec) in FIG. 5 (a), and is constant at 18.5 ppm. The time from the start to the end of printing for each number of prints is shown in Table 6, which is shown by the broken line in FIG. 5 (b).

(Table 6) Printing time at 100 mm / sec

Here, assuming that the user prints at the ratio of use case 1, when printing 100 jobs, the total print time required is 1838 seconds from Table 7.

(Table 7) Use case 1: Time required for 100 jobs (Comparative example 2)

Next, assuming that the user prints at the ratio of use case 2, when printing 100 jobs, the total print time required is 2755 seconds from Table 8.

(Table 8) Use case 2: Time required for 100 jobs (Comparative example 1)

Next, the control of this embodiment will be described. In this embodiment, the image forming speed is switched according to the operation history of the image forming apparatus. That is, the print operation is executed using different image formation speeds depending on the use case. The number of images to be switched at the predetermined image formation speed in this embodiment is set to 6. That is, if the average value of the number of continuous prints for each paper size calculated by the print operation history analysis unit 508 is less than 6, printing is performed at the first image formation speed, and if it is 6 or more, the second is performed. Print at the second image formation speed. Here, when the job is executed at the ratio of the use case 1, the average value of the number of continuous prints is 3.5 as the operation history. On the other hand, when the job is executed at the ratio of use case 2, the average value of the number of continuous prints is 6.3 as the operation history.

Therefore, when the control of the first embodiment is performed, in the case of the use case 1, B5 size paper is printed at 200 mm / sec, so that when 100 jobs are printed, the total printing time is 1729 seconds. Further, in the case of use case 2, since printing is performed at 100 mm / sec, when printing 100 jobs, the total printing time is 2755 seconds.
Table 9 shows a comparison of the total print times when the above 100 jobs are printed.

(Table 9) Comparison of total print time for 100 jobs

In the case of Comparative Example 1, since the image formation speed is 200 mm / sec, printing can be completed in less time than in Comparative Example 2 when the ratio of a small number of jobs is large as in use case 1. However, when the ratio of a large number of jobs is large as in use case 2, the print time is longer than that in Comparative Example 2. Further, in Comparative Example 2, on the contrary, in the use case 1, the printing time is extended, but in the use case 2, the printing is completed in a short time.

On the other hand, in the first embodiment, since the control of switching the image formation speed is performed according to the operation history, the printing can be completed in the minimum time in both the use case 1 and the use case 2.

As described above, in this embodiment, the operation history of the image forming apparatus is stored, the average value of the number of continuous prints is calculated for each paper size, and this average value is compared with the predetermined number of speed switching sheets. , Determine the image formation rate. Therefore, the optimum image formation speed can be selected for each use case, and the print productivity can be maximized. Further, in this embodiment, the predetermined number of image speed switching sheets is set to 6 for B5 size paper, but the number of switching sheets may be changed for each paper size.
That is, in this embodiment, the judgment reference value of the control selection reflects the operation history that is updated every time it is used. It is possible to more optimally control the fixing operation according to the tendency of the number of printed sheets of the user, and it is possible to improve the productivity and extend the life of the device by reducing the load on the device components. It should be noted that the history information stored in the storage unit only needs to include at least the number of continuous paper sheets for the recording material of the size in which the temperature rise of the non-passing paper portion becomes a problem, and the recording material of all the sizes that can be conveyed It may be configured not to remember about.

[Example 2]
In this embodiment, the operation history is analyzed for each user ID as the operation history of the image forming apparatus. The configuration of the image forming apparatus, the image heating apparatus, and the control block of the second embodiment is the same as that of the first embodiment, and the matters not particularly described here in the second embodiment are the same as those of the first embodiment.

The print operation history collection unit 506 of this embodiment collects paper size information, continuous print number information, and user ID information for each print job and stores them in the storage device 469. Here, the user ID information uniquely identifies the user ID in order to distinguish each host computer when the image forming apparatus is connected to and installed on a plurality of external devices 501 (host computers) via a network. Set. Table 10 shows an example of the operation history stored in the storage device 469. The history can store the latest 500 jobs. User IDs are assigned in order from "001" for each host computer connected via the network.

(Table 10) Print operation history

Next, Table 11 shows an example of the analysis result of the print operation history in this embodiment. The average value of the number of continuous prints is calculated for each user ID and paper size, and the result is stored in the storage device 469.

(Table 11) Print operation history analysis

In this embodiment, the average value of the number of continuous prints is used as the representative value of the analysis result, but not only the average value but also the median value, the mode value, and the standard deviation may be combined.

[Control method of image formation operation]
FIG. 7 is a control flowchart in this embodiment.
Upon receiving the image information and the print instruction transmitted from the external device 501 in S701, the video controller 120 starts the work of converting the image information into printable information. In addition, the control unit 113 is instructed to perform a preparatory operation.

The image formation control unit 502 included in the control unit 113 in S702 receives the preparatory operation instruction and determines whether or not the number of print jobs has been determined.

When the number of print jobs is fixed in S702, the image formation control unit 502 receives the number of print jobs from the video controller 120 in S703.
In S704, the number of print jobs is compared with the predetermined number of speed switching, and if the number of print jobs is smaller, printing is executed at the first image forming speed in S705. On the other hand, when the number of print job sheets is larger than the predetermined speed switching number in S704, printing is executed at the second image forming speed in S706.

If the number of print jobs is not fixed in S702, user ID information is acquired from the external device 501 in S707.
In S708, the print operation history analysis unit 508 acquires the print operation history analysis result corresponding to the user ID and the paper size information designated from the storage device 469.
If the average value of the number of continuous prints of the paper size specified in the print job is less than the predetermined number of speed switching sheets from the print operation history analysis result in S709, printing is executed at the first image formation speed in S710. .. On the other hand, in S709, when the average value of the number of continuous prints is larger than the predetermined number of speed switching sheets (in the case of the number of speed switching sheets or more), printing is executed at the second image forming speed in S711.

When all the print jobs have been printed in S712, the print operation history collection unit 506 stores the number of print jobs in the storage device 469 in S713.
In S714, the print operation history analysis unit 508 acquires the latest print operation history from the storage device 469, calculates the average value of the user ID and the number of continuous prints for each paper size, and stores them in the storage device 469.

As described above, in this embodiment, a user ID is assigned to each host computer connected via the network, and the operation history of each user ID is analyzed. Therefore, since a use case corresponding to the user ID can be assumed, the print productivity can be maximized by selecting the optimum image formation speed for each user ID.

[Example 3]
In this embodiment, the predetermined number of images for determining the switching of the image forming speed is variable depending on the environmental temperature in which the image forming apparatus is installed. The configuration of the image forming device, the image heating device, and the control block of the third embodiment is the same as that of the first embodiment except that the environmental temperature detection sensor 490 is provided as the environmental information acquisition unit as shown in FIG. Matters not particularly described here in Example 3 are the same as those in Examples 1 and 2.
The information acquired as environmental information may be humidity, absolute water content, etc., in addition to temperature.

FIG. 8A shows a case where B5 size paper is passed at a first image forming speed (200 mm / sec) and a second image forming speed (100 mm / sec) when the environmental temperature is 20 ° C. It is a graph which shows the relationship between the number of continuous prints [page], and the throughput. Further, FIG. 8B is a similar graph when the environmental temperature is 30 ° C.
In the case of FIG. 8 (b) where the environmental temperature is 30 ° C., the amount of heat required for fixing is smaller than that in FIG. 8 (a) where the environmental temperature is 20 ° C., so the set temperature of the fuser is lowered. be able to. Therefore, since the temperature rise of the non-paper-passing portion is also suppressed, when the image formation speed is 200 mm / sec, even if the throughput is gradually reduced, the reduction width becomes gradual. On the other hand, when the image forming speed is 100 mm / sec, the throughput decrease due to the temperature rise of the non-passing portion does not occur regardless of the environmental temperature.

Next, FIG. 9 shows the time from the start to the end of printing for each number of prints. FIG. 9A shows the time when printing was performed with throughput control when the environmental temperature was 20 ° C., and FIG. 9B shows the time when printing was performed under throughput control when the environmental temperature was 30 ° C. is there. In FIG. 9A, when the number of printed sheets is 6 or less, the productivity is higher when printing at 200 mm / sec, but when the number of printed sheets is 7 or more, the productivity is higher when printing at 100 mm / sec. Understand. On the other hand, in FIG. 9B, it can be seen that the productivity of the image forming speed of 200 mm / sec and the image forming speed of 100 mm / sec are reversed with the number of printed sheets being 10 as a boundary. That is, when the environmental temperature is high, the print productivity is maximized by setting a large number of predetermined prints for determining the switching of the image formation speed.

[Control method of image formation operation]
FIG. 10 is a control flowchart in this embodiment.
In S101, when the video controller 120 receives the image information and the print instruction transmitted from the external device 501, the video controller 120 starts the work of converting the image information into printable information. In addition, the control unit 113 is instructed to perform a preparatory operation.

In S102, the control unit 113 acquires the environmental temperature from the environmental temperature detection sensor 490 installed in the image forming apparatus.
In S103, the number of speed switches for each environmental temperature is set. Table 12 shows the number of image formation speeds that can be switched for each environmental temperature when the B5 size paper in this embodiment is continuously printed.

(Table 12)

In S104, the control unit 113 determines whether or not the number of print jobs has been determined.

If the number of print jobs is fixed in S104, the image formation control unit 502 receives the number of print jobs from the video controller 120 in S105.
In S106, the number of print jobs is compared with the number of speed switching sheets set in S103, and if the number of print jobs is smaller, printing is executed at the first image forming speed in S107. On the other hand, when the number of print job sheets is larger than the number of speed switching sheets in S106, printing is executed at the second image forming speed in S108.

If the number of print jobs is not fixed in S104, and the average value of the number of continuous prints of the paper size specified in the print job is less than the speed switching number from the print operation history analysis result in S109, S110 Print at the first image formation speed. On the other hand, in S109, when the average value of the number of continuous prints is larger than the number of speed switching sheets (when the number of speed switching sheets or more), printing is executed at the second image forming speed in S111.

After printing all the print jobs in S112, the print operation history collection unit 506 stores the number of print jobs in the storage device 469 in S113.
In S114, the print operation history analysis unit 508 acquires the latest print operation history from the storage device 469, calculates the average value of the number of continuous prints, and stores it in the storage device 469.

As described above, in this embodiment, the number of images for determining the switching of the image forming speed is variable depending on the environmental temperature in which the image forming apparatus is installed. Print productivity can be maximized by selecting the optimum image formation rate for each environmental temperature.

[Example 4]
[Control block configuration]
FIG. 12 shows a control block diagram in this embodiment. The video controller 120 stores the print operation history and analyzes the print operation history. When the video controller 120 receives the image information and the print instruction from the external device 501, the video controller 120 instructs the control unit 113 to perform a preparatory operation. After that, the video controller 120 converts the image information into printable information, and instructs the control unit 113 to perform a print operation (image formation operation). The control unit 113 starts the printing operation in response to an instruction from the video controller 120.

The print operation history collecting unit 122 stores the print operation history in the storage device (storage unit) 124. Further, as in the case of the first embodiment, one job is set until all the prints are completed. The print operation history collection unit 122 acquires information on how many sheets are continuously printed in one job and paper size information as a print operation history, and stores the information in the storage device 124. Further, the print operation history collection unit 122 may collect the paper size information, the continuous print number information, and the user ID information for each print job and store them in the storage device 124. The print operation history collection unit 122 may perform the same processing as the processing performed by the print operation history collection unit 506 shown in Examples 1 to 3.

The print operation history analysis unit 123 stores the analysis result of the print operation history in the storage device 124. The print operation history analysis unit 123 calculates the average value of the number of continuous prints per job for each paper size. Further, the result calculated by the print operation history analysis unit 123 is also stored in the storage device 124. The print operation history analysis unit 123 may perform the same processing as the processing performed by the print operation history analysis unit 508 shown in Examples 1 to 3. The information stored in the storage device 469 shown in Examples 1 to 3 may be stored in the storage device 124. Since the control method of the image formation operation and the throughput control method using the analysis result of the print operation history in this embodiment are the same as those in the first embodiment, the description thereof will be omitted.

[Example 5]
The image forming system according to this embodiment will be described.
[Control block configuration]
FIG. 13 shows a control block diagram in this embodiment. The image forming system includes an image forming apparatus 100 and a server 600. The server 600 stores the print operation history and analyzes the print operation history. The server 600 has an arithmetic unit 601 and a server storage device 604, and is connected to the image forming device 100 by a bidirectionally accessible network. When the video controller 120 receives the image information and the print instruction from the external device 501, the video controller 120 instructs the control unit 113 to perform a preparatory operation. After that, the video controller 120 converts the image information into printable information, and instructs the control unit 113 to perform a print operation (image formation operation). The control unit 113 starts the printing operation in response to an instruction from the video controller 120.

The print operation history collection unit 602 stores the print operation history in the server storage device (storage unit) 604. Further, as in the case of the first embodiment, one job is set until all the prints are completed. The print operation history collection unit 602 acquires information on how many sheets are continuously printed in one job and paper size information as a print operation history, and stores the information in the server storage device 604. Further, the print operation history collection unit 602 may collect paper size information, continuous print number information, and user ID information for each print job and store them in the server storage device 604. The print operation history collection unit 602 may perform the same processing as the processing performed by the print operation history collection unit 506 shown in Examples 1 to 3.

The print operation history analysis unit 603 stores the analysis result of the print operation history in the server storage device 604. The print operation history analysis unit 603 calculates the average value of the number of continuous prints per job for each paper size. Further, the result calculated by the print operation history analysis unit 603 is also stored in the server storage device 604. The print operation history analysis unit 603 may perform the same processing as the processing performed by the print operation history analysis unit 508 shown in Examples 1 to 3. The information stored in the storage device 469 shown in Examples 1 to 3 may be stored in the server storage device 604. Since the control method of the image formation operation and the throughput control method using the analysis result of the print operation history in this embodiment are the same as those in the first embodiment, the description thereof will be omitted.

Each of the above embodiments can be combined with each other as much as possible.

100 ... image forming device, 113 ... control unit, 200 ... fixing device (image heating device), 300 ... heater, 469 ... storage device (storage unit), 501 ... external device, 502 ... image forming control unit

Claims (16)

An image forming part that forms an image on the recording material,
A fixing portion having a nip portion for sandwiching and transporting the recording material and heating the image in the nip portion to fix the image to the recording material.
At least during continuous paper passing, the recording material having a width narrower than that of the recording material having the maximum width in the direction orthogonal to the transport direction among the recording materials that can be conveyed by the nip portion is continuously passed through the nip portion. A storage unit that stores the number of recording materials having a narrow width in the above as a history for each continuous paper passing.
A control unit that controls the transport speed of the recording material when passing through the nip unit,
In an image forming apparatus including
The control unit
When the narrow recording material is continuously passed through the paper,
When the representative value of the number of sheets of the narrow recording material acquired from the history in one continuous paper passing is smaller than a predetermined threshold value, the first transport speed is controlled to the first speed. Run the operating mode,
When the representative value is equal to or higher than the threshold value, the transport interval of the recording material during continuous paper passing is the same as that of the first operation mode, and the transport speed is slower than the first speed. An image forming apparatus, characterized in that a second operation mode is executed. Further provided with a temperature detecting unit for detecting the temperature of the fixing unit,
The control unit is characterized in that, in the first operation mode, the transport interval of the recording material during continuous paper passing is controlled so that the temperature detected by the temperature detection unit maintains a predetermined target temperature. The image forming apparatus according to claim 1. The image forming apparatus according to claim 1 or 2, wherein the control unit controls the transport interval to be constant in the first operation mode. The representative value according to any one of claims 1 to 3, wherein the representative value is any one of the average value, the median value, and the mode value of the number of sheets in one continuous paper passing. Image forming device. The image forming apparatus according to any one of claims 1 to 4, wherein the storage unit stores the history for each size of the recording material that can be conveyed by the nip unit. The image forming apparatus is connected to a plurality of external devices via a network.
The image forming apparatus according to any one of claims 1 to 5, wherein the storage unit stores the history for each of the plurality of external devices. An environmental information acquisition unit for acquiring environmental information in which the image forming apparatus is installed is further provided.
The image forming apparatus according to any one of claims 1 to 6, wherein the threshold value is set according to the environmental information acquired by the environmental information acquisition unit. The fixing part is
A heater unit having a heater and a holding member for holding the heater,
A tubular film whose inner surface contacts the heater unit,
A pressure member that comes into contact with the outer surface of the film and forms the nip portion between the outer surface and the film.
The image forming apparatus according to any one of claims 1 to 7, wherein the image forming apparatus is provided. It has an image forming portion that forms an image on the recording material, a nip portion that sandwiches and conveys the recording material, and passes through the nip portion, a fixing portion that heats the image in the nip portion and fixes the image to the recording material, and the nip portion. An image forming apparatus including a control unit for controlling the transport speed of the recording material at the time of
It is connected to the image forming apparatus by a bidirectionally accessible network, and at least the width of the recording material that can be conveyed by the nip portion is larger than that of the recording material having the maximum width in the direction orthogonal to the conveying direction. A server including a storage unit that stores the number of recording materials having a narrow width at the time of continuous paper passing through the nip portion of a narrow recording material as a history for each continuous paper passing.
In an image forming system that has
The control unit
When the narrow recording material is continuously passed through the paper,
When the representative value of the number of sheets of the narrow recording material acquired from the history in one continuous paper passing is smaller than a predetermined threshold value, the first transport speed is controlled to the first speed. Run the operating mode,
When the representative value is equal to or higher than the threshold value, the transport interval of the recording material during continuous paper passing is the same as that of the first operation mode, and the transport speed is slower than the first speed. An image forming system characterized in that a second operation mode is executed. The image forming apparatus further includes a temperature detecting unit that detects the temperature of the fixing unit.
The control unit is characterized in that, in the first operation mode, the transport interval of the recording material during continuous paper passing is controlled so that the temperature detected by the temperature detection unit maintains a predetermined target temperature. 9. The image forming system according to claim 9. The image forming system according to claim 9 or 10, wherein the control unit controls the transport interval to be constant in the first operation mode. The representative value according to any one of claims 9 to 11, wherein the representative value is any one of the average value, the median value, and the mode value of the number of sheets in one continuous paper passing. Image formation system. The image forming system according to any one of claims 9 to 12, wherein the storage unit stores the history for each size of the recording material that can be conveyed by the nip unit. The image forming apparatus is connected to a plurality of external devices via a network.
The image forming system according to any one of claims 9 to 13, wherein the storage unit stores the history for each of the plurality of external devices. The image forming apparatus further includes an environmental information acquisition unit that acquires environmental information in which the image forming apparatus is installed.
The image forming system according to any one of claims 9 to 14, wherein the threshold value is set according to the environmental information acquired by the environmental information acquisition unit. The fixing part is
A heater unit having a heater and a holding member for holding the heater,
A tubular film whose inner surface contacts the heater unit,
A pressure member that comes into contact with the outer surface of the film and forms the nip portion between the outer surface and the film.
The image forming system according to any one of claims 9 to 15, further comprising.

Images