Image forming device

Abstract

To more appropriately execute printing operation restriction control.SOLUTION: An image forming apparatus 100 has: an image forming unit 20 that forms images; a driving device 74 that drives the image forming unit 20; an external apparatus temperature sensor 71 that detects the temperature outside the apparatus; an internal apparatus temperature sensor 72 that detects the temperature inside the apparatus; a work amount detection unit 73 that detects the amount of work performed by the image forming unit 20; and a control unit 70 that controls the operation of the image forming unit 20. When the temperature detected by the external apparatus temperature sensor 71 is less than a predetermined environmental temperature threshold TA, the control unit 70 makes a transition to a first print operation restriction state based on the amount of work performed by the image forming unit 20 detected by the work amount detection unit 73. In the first print operation restriction state, every time the amount of work performed by the image forming unit 20 reaches a predetermined work amount threshold Pt, the drive of the image forming unit 20 performed by the driving device 74 is temporarily stopped over a predetermined period.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus. [Background technology]

[0002] 2. Description of the Related Art In an image forming apparatus, there is a technique for restricting a printing operation when print quality is adversely affected.

[0003] Patent document 1 describes a technology that detects the temperature inside or around a developing device, which changes in response to the temperature of a developer carrier, and based on the detection results, controls the limit on the number of pages that can be continuously imaged and the lifting of that limit, and notifies the time information when the operation to limit the number of pages that can be continuously imaged is executed. Summary of the Invention [Problem to be solved by the invention]

[0004] Due to layout constraints and cost considerations, it is necessary to shift the positional relationship between the heat-generating part whose temperature you want to control and the internal temperature sensor, so it is not possible to restrict printing operations at appropriate times depending on the machine's installation environment.

[0005] An object of the present invention is to more appropriately implement restriction control of a printing operation. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, an image forming apparatus according to one aspect of the present invention includes an image forming unit that forms an image, a drive unit that drives the image forming unit, an outside-machine temperature detection unit that detects a temperature outside the machine, an inside-machine temperature detection unit that detects a temperature inside the machine, a workload detection unit that detects a workload of the image forming unit, and a control unit that controls an operation of the drive unit, and when the temperature detected by the outside-machine temperature detection unit is less than a predetermined environmental temperature threshold, the control unit transitions to a first print operation restriction state based on the workload detected by the workload detection unit, and the first print operation restriction state is maintained when the workload is greater than a predetermined threshold. The control unit temporarily stops driving the image creating unit by the drive device for a predetermined period of time each time a certain workload threshold is reached, and when the temperature detected by the outside-machine temperature detection unit is equal to or higher than the environmental temperature threshold, the control unit transitions to a second printing operation restriction state based on the inside-machine temperature detected by the inside-machine temperature detection unit, and the second printing operation restriction state performs intermittent operation by repeating a pause state in which driving of the image creating unit by the drive device is stopped and a printing state in which the image creating unit is driven when the inside-machine temperature is higher than a predetermined first threshold, until the inside-machine temperature falls below a second threshold lower than the first threshold. Effect of the Invention

[0007] This makes it possible to more appropriately implement restriction control of the printing operation. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing an example of a configuration of an image forming apparatus according to an embodiment; [Diagram 2] FIG. 2 is a diagram showing an example of the configuration of an image forming unit; [Diagram 3] FIG. 1 is a block diagram showing an example of a hardware configuration of an image forming apparatus. [Figure 4] Block diagram showing the main configuration of the control system of the imaging unit [Diagram 5] FIG. 1 is a sequence diagram of an example of a conventional print operation restriction mode. [Figure 6] FIG. 11 is a sequence diagram of another example of a conventional print operation restriction mode; [Figure 7] FIG. 1 is a sequence diagram of a print operation restriction mode according to the present embodiment. [Figure 8] Flowchart of print operation restriction mode control according to the present embodiment [Figure 9] First modified example of the flowchart for print operation restriction mode control [Figure 10] Second Modification of Flowchart of Printing Operation Restriction Mode Control DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment will be described with reference to the accompanying drawings. In order to facilitate understanding of the description, the same components in each drawing are denoted by the same reference numerals as much as possible, and duplicated description will be omitted.

[0010] Hereinafter, an embodiment will be described taking as an example an electrophotographic image forming apparatus equipped with a secondary transfer mechanism called a tandem system.

[0011] This image forming device is an MFP (Multifunction Peripheral / Printer / Product) that has copy, print, and facsimile functions in one housing. In addition, examples of recording media include plain paper generally used for copying, overhead projector sheets (OHP sheets), thick paper such as cards and postcards, and envelopes, but here, paper P will be described as an example of a recording medium.

[0012] <Configuration Example of Image Forming Apparatus 100> Fig. 1 is a diagram showing an example of the configuration of an image forming apparatus 100 according to an embodiment, and is a cross-sectional view showing a main part of the image forming apparatus 100 according to the embodiment. As shown in Fig. 1, the image forming apparatus 100 has an intermediate transfer unit at the center, which has an intermediate transfer belt 10 that is an endless belt. The intermediate transfer belt 10 is wound around three support rollers 14 to 16, and is driven to rotate clockwise.

[0013] Furthermore, the image forming apparatus 100 includes an intermediate transfer member cleaning unit 17, located to the left of the second support roller 15 of the three support rollers 14-16, for removing residual toner remaining on the intermediate transfer belt 10 after image transfer.

[0014] An imaging unit 20 consisting of a yellow (Y) imaging unit, a magenta (M) imaging unit, a cyan (C) imaging unit, and a black (K) imaging unit is provided facing the intermediate transfer belt 10 arranged between the first support roller 14 and the second support roller 15, and the imaging units of each color are arranged along the movement direction of the intermediate transfer belt 10.

[0015] The imaging units for each color have the same configuration except for the toner colors they use, so in the explanations and drawings, the suffixes "Y", "M", "C", and "K" indicating the toner colors used will be omitted as appropriate.

[0016] The image forming section 20 includes photoconductor drums 40 for each color, a charging roller 18, a developing unit, and a cleaning unit, and is detachably mounted on the image forming apparatus 100.

[0017] The image forming apparatus 100 is provided with a cover section that can be opened and closed by tilting it forward (toward the viewer on the page) in order to protect the inside of the image forming apparatus 100. A user of the image forming apparatus 100 or a serviceman performing maintenance can open the cover section to access the inside of the image forming apparatus 100 and attach and detach the imaging unit 20 to and from a predetermined position within the image forming apparatus 100.

[0018] The image forming section 20 is, for example, a process cartridge drum unit (hereinafter, referred to as PCDU) that is replaceable depending on the life of the photosensitive drum 40.

[0019] Moreover, the image forming apparatus 100 includes a light beam scanning unit 21 above the image creating unit 20. The light beam scanning unit 21 can form an electrostatic latent image corresponding to image data on the photoconductor drum 40 of each color by irradiating the photoconductor drum 40 of each color with a light beam (laser light) for image formation.

[0020] The electrostatic latent images on the photoconductor drums 40 of each color are developed by the developing units, and the developed toner images of each color are superimposed and primarily transferred onto the intermediate transfer belt 10. As a result, a color toner image is formed on the intermediate transfer belt 10. The toner image is carried on the intermediate transfer belt 10, which is an example of an image carrier, and moves along the direction of movement of the intermediate transfer belt 10. The configuration of the image creating unit 20 will be described in detail separately with reference to FIG. 2.

[0021] The image forming apparatus 100 also includes a secondary transfer unit 22 below the intermediate transfer belt 10. The secondary transfer unit 22 is disposed so that a secondary transfer belt 24, which is an endless belt, is suspended between two rollers 23 and pushes up the intermediate transfer belt 10 and presses it against a third support roller 16. The secondary transfer belt 24 can secondarily transfer the toner image formed on the intermediate transfer belt 10 onto the paper P.

[0022] Furthermore, the image forming apparatus 100 includes a fixing unit 25 on the side of the secondary transfer device 22. The fixing unit 25 fixes the toner image on the paper P that has been transported with the toner image secondarily transferred onto the paper P. The fixing unit 25 includes a fixing belt 26, which is an endless belt, a heating roller, and a pressure roller 27, and can fix the toner image transferred onto the surface of the paper P onto the paper P by the heat and pressure of the fixing belt 26 and the pressure roller 27.

[0023] In addition, the image forming apparatus 100 is provided below the secondary transfer unit 22 and the fixing unit 25 with a sheet inversion unit 28 that inverts the paper P and sends it out so that an image can be formed on the back side of the paper P immediately after an image has been formed on the front side.

[0024] Next, a series of steps for forming an image on paper P in image forming apparatus 100 will be described.

[0025] When a "copy" start button on an operation unit (not shown) is pressed, image forming apparatus 100 causes ADF (Auto Document Feeder) 400, which is an automatic document transport unit, to transport the document onto contact glass 32 if the document is placed on document feed tray 30 of ADF 400. On the other hand, if no document is placed on document feed tray 30, image reading unit 300 including first carriage 33 and second carriage 34 is driven to read a document manually placed on contact glass 32.

[0026] In the image reading unit 300, a light source included in a first carriage 33 irradiates light onto a contact glass 32. The light reflected from the document surface is reflected by a first mirror included in the first carriage 33 toward a second carriage 34, and is reflected by a mirror included in the second carriage 34. The light reflected from the document surface is then imaged by an imaging lens 35 on an imaging surface of a CCD (Charge Coupled Device) 36, which is a reading sensor. The CCD 36 captures an image of the document surface, and image data for each color of Y, M, C, and BK is generated based on the image signal captured by the CCD 36.

[0027] In addition, when the "Print" start button is pressed, when an instruction to form an image is received from an external device such as a PC (Personal Computer), or when an instruction to output a FAX (Facsimile) is received, the image forming apparatus 100 starts the rotational drive of the intermediate transfer belt 10 and prepares each unit of the image forming section 20 for image formation.

[0028] Then, the image forming apparatus 100 starts the image forming process for each color. A laser modulated based on image data for each color is irradiated onto the photoconductor drum 40 for each color, and an electrostatic latent image is formed. Then, the toner images of each color developed from the electrostatic latent image are superimposed on the intermediate transfer belt 10 to form a single image.

[0029] Thereafter, the paper P is fed into the secondary transfer unit 22 at the same time that the leading edge of the toner image on the intermediate transfer belt 10 enters the secondary transfer unit 22. The toner image on the intermediate transfer belt 10 is then secondarily transferred onto the paper P by the secondary transfer unit 22. The paper P onto which the toner image has been secondarily transferred is fed into the fixing unit 25, where the toner image is fixed onto the paper P.

[0030] Here, the feeding of the paper P to the secondary transfer position will be described. When one of the paper feed rollers 42 of the paper feed table 200 is rotated, the paper P is fed from one of the paper feed trays 44 provided in the paper feed unit 43. Then, only one sheet is separated by the separation roller 45, enters the transport roller unit 46, and is transported by the transport roller 47. Then, the paper P is guided to the transport roller unit 48 in the image forming apparatus 100, abuts against the registration roller 49 of the transport roller unit 48, and is temporarily stopped, and then, as described above, is sent toward the secondary transfer unit 22 in accordance with the timing of the secondary transfer.

[0031] Also, the user can feed the paper P by inserting it into the manual feed tray 51. When the user inserts the paper P into the manual feed tray 51, the image forming apparatus 100 rotates the paper feed roller 50 to separate one sheet of the paper P on the manual feed tray 51 and pull it into the manual feed path 53. Then, as in the above, the paper hits the registration roller 49, stops once, and then sends it to the secondary transfer unit 22 in accordance with the timing of the secondary transfer described above.

[0032] The paper P that has been fixed by the fixing unit 25 and discharged is guided by the switching claw 55 to the discharge rollers 56, discharged by the discharge rollers 56, and stacked on the paper discharge tray 57. Alternatively, the paper P is guided by the switching claw 55 to the sheet inversion unit 28, inverted by the sheet inversion unit 28, and led to the secondary transfer position again. Thereafter, an image is formed on the rear side of the paper P, and the paper P is discharged by the discharge rollers 56 onto the paper discharge tray 57.

[0033] On the other hand, residual toner remaining on the intermediate transfer belt 10 after the image transfer is removed by an intermediate transfer body cleaning unit 17, in preparation for next image formation.

[0034] In this manner, the image forming apparatus 100 can form a color image on the paper P.

[0035] <Configuration example of the imaging unit 20> Next, the configuration of the image forming unit 20 in the image forming apparatus 100 will be described with reference to FIG.

[0036] FIG. 2 is a diagram showing an example of the configuration of the image forming unit 20, and shows an example of the configuration of one of the image forming units for each color. As described above, the image forming units for the other three colors have the same configuration except for the toner colors used, so illustration and description are omitted and only one image forming unit will be described. The image forming unit 20 includes a photoconductor drum 40, a charging roller 18, a developing unit 29, a cleaning blade 13, a static eliminator 19, and a primary transfer roller 62. A charging high voltage power supply 181 is electrically connected to the charging roller 18, and a transfer high voltage power supply 621 is electrically connected to the primary transfer roller 62.

[0037] The photoconductor drum 40, which is an example of an image carrier, is a negatively charged organic photoconductor, and is formed by providing a photosensitive layer, etc., on a drum-shaped conductive support. The photoconductor drum 40 is formed by sequentially laminating an undercoat layer, which is an insulating layer, a charge generating layer and a charge transport layer, which are photosensitive layers, and a protective layer, i.e., a surface layer, on the conductive support, which is a base layer. The conductive support of the photoconductor drum 40 can be made of a conductive material, etc., having a volume resistivity of 1010 Ωcm or less.

[0038] The charging roller 18 is a roller member formed by covering the outer periphery of a conductive core metal with an elastic layer of medium resistance. A predetermined voltage is applied from a charging high-voltage power supply 181 to uniformly charge the surface of the photoconductor drum 40 facing the charging roller 18. A cleaning roller for removing dirt from the charging roller 18 may be provided in contact with the charging roller 18.

[0039] A small gap is provided between the charging roller 18 and the photosensitive drum 40, and the charging roller 18 is disposed in a non-contact state with respect to the photosensitive drum 40. A charging method in which the photosensitive drum 40 is charged in this state is called a non-contact charging method.

[0040] In the non-contact charging method, foreign matter such as toner and lubricant remaining on the photosensitive drum 40 is less likely to adhere to the charging roller 18 than in the contact charging method in which charging is performed by contacting the charging roller 18 with the photosensitive drum 40, and therefore uneven charging due to adhesion of foreign matter can be suppressed. However, the embodiment is not limited to the non-contact charging method, and may be applied to the contact charging method. The charging high voltage power supply 181 applies a charging bias to the charging roller 18.

[0041] The developing unit 29 has a developing roller 29a facing the photosensitive drum 40. The developing roller 29a is equipped with a magnet that is fixed inside and forms a magnetic pole on the peripheral surface of the roller, and a sleeve that rotates around the magnet. The magnet forms multiple magnetic poles on the developing roller 29a, and the developer is carried on the developing roller 29a.

[0042] The cleaning blade 13 mechanically scrapes off untransferred toner and other deposits adhering to the surface of the photoreceptor drum 40. The cleaning blade 13 is a blade-like member made of a rubber material such as urethane rubber and formed into a substantially plate-like shape, and contacts the surface of the photoreceptor drum 40 at a predetermined angle and with a predetermined pressure.

[0043] After the toner image is transferred, the charge remover 19 removes the charge on the surface of the photoconductor drum 40. The photoconductor drum 40, which has been uniformly charged by the charging roller 18, is exposed to a light beam from the light beam scanning unit 21 in accordance with image data. An electrostatic latent image is formed on the surface of the photoconductor drum 40. The developer 29 attaches toner to the electrostatic latent image formed on the surface of the photoconductor drum 40. As a result, a toner image is developed on the surface of the photoconductor drum 40.

[0044] When a voltage generated by a transfer high-voltage power supply 621 is applied to the primary transfer roller 62, the toner image on the surface of the photoconductor drum 40 is transferred to the intermediate transfer belt 10. The toner image on the intermediate transfer belt 10 is transferred to paper P by the secondary transfer unit 22 and fixed to the paper P by the fixing unit 25. Residual toner and the like on the surface of the photoconductor drum is removed by a cleaning blade 13. In addition, the charge on the surface of the photoconductor drum 40 is removed by a static eliminator 19.

[0045] <Example of Hardware Configuration of Image Forming Apparatus 100> Next, a description will be given of a hardware configuration of the image forming apparatus 100. FIG 3 is a block diagram showing an example of a hardware configuration of the image forming apparatus 100.

[0046] As shown in FIG. 3, the image forming apparatus 100 includes a controller 910, a short-range communication circuit 920, an engine control unit 930, an operation panel 940, a network I / F 950, and a control board 960.

[0047] Of these, the controller 910 includes a CPU 901 which is the main part of the computer, a system memory (MEM-P) 902, a north bridge (NB) 903, a south bridge (SB) 904, an ASIC (Application Specific Integrated Circuit) 906, a local memory (MEM-C) 907 which is a storage unit, an HDD controller 908, and a HD 909 which is a storage unit. The NB 903 and the ASIC 906 are connected by an AGP (Accelerated Graphics Port) bus 921.

[0048] Of these, the CPU (Central Processing Unit) 901 is a control unit that performs overall control of the image forming apparatus 100. The NB 903 is a bridge for connecting the CPU 901 with the MEM-P 902, the SB 904, and the AGP bus 921, and includes a memory controller that controls reading and writing to the MEM-P 902, a PCI (Peripheral Component Interconnect) master, and an AGP target.

[0049] The MEM-P 902 consists of a ROM (Read Only Memory) 902a, which is a memory for storing programs and data that realize each function of the controller 910, and a RAM (Random Access Memory) 902b, which is used for expanding programs and data, and as a drawing memory during memory printing.

[0050] The programs stored in the RAM 902b may be provided by being recorded on a computer-readable recording medium such as a CD-ROM, CD-R, or DVD in the form of an installable or executable file.

[0051] The SB 904 is a bridge for connecting the NB 903 with PCI devices and peripheral devices. The ASIC 906 is an IC (Integrated Circuit) for image processing purposes that has hardware elements for image processing, and serves as a bridge for connecting the AGP bus 921, the PCI bus 922, the HDD 908, and the MEM-C 907.

[0052] This ASIC 906 consists of a PCI target and AGP master, an arbiter (ARB) which forms the core of the ASIC 906, a memory controller which controls the MEM-C 907, multiple DMACs (Direct Memory Access Controllers) which perform operations such as rotating image data using hardware logic, and a PCI unit which transfers data between a scanner unit 931 and a printer unit 932 via a PCI bus 922.

[0053] It should be noted that the ASIC 906 may be connected to a USB interface or an IEEE1394 (Institute of Electrical and Electronics Engineers 1394) interface.

[0054] The MEM-C 907 is a local memory used as an image buffer for copying and a code buffer. The HD 909 is a storage for storing image data, font data used during printing, and forms. The HD 909 controls the reading and writing of data from and to the HD 909 under the control of the CPU 901.

[0055] The AGP bus 921 is a bus interface for a graphics accelerator card proposed to speed up graphic processing, and by directly accessing the MEM-P 902 at high throughput, the graphics accelerator card can be made faster.

[0056] Further, the short-distance communication circuit 920 includes a short-distance communication circuit 920a. The short-distance communication circuit 920 is a communication circuit such as NFC or Bluetooth (registered trademark).

[0057] Furthermore, the engine control unit 930 is made up of a scanner unit 931 and a printer unit 932. It should be noted that the image forming unit 20 described with reference to FIG.

[0058] The operation panel 940 is equipped with a panel display unit 940a, such as a touch panel, which displays current setting values ​​and selection screens, etc., and accepts input from the operator, and an operation panel 940b consisting of a numeric keypad which accepts setting values ​​for image formation conditions, such as density setting conditions, and a start key which accepts a copy start instruction.

[0059] The controller 910 controls the entire image forming apparatus 100, for example, controlling drawing, communication, and input from an operation panel 940. The scanner unit 931 or the printer unit 932 includes an image processing unit that performs error diffusion, gamma conversion, and the like.

[0060] In addition, the image forming apparatus 100 can select the document box function, copy function, printer function, and facsimile function by sequentially switching between them using the application switching key on the operation panel 940.

[0061] When the document box function is selected, the document box mode is selected; when the copy function is selected, the copy mode is selected; when the printer function is selected, the printer mode is selected; and when the facsimile mode is selected, the facsimile mode is selected.

[0062] The network I / F 950 is an interface for performing data communication using a network. The short-range communication circuit 920 and the network I / F 950 are electrically connected to the ASIC 906 via a PCI bus 922.

[0063] <Control system of the imaging unit 20> Fig. 4 is a block diagram showing the main configuration of a control system for the image forming unit 20. As shown in Fig. 4, the image forming apparatus 100 includes a control unit 70, an external temperature sensor 71 (external temperature detection unit), an internal temperature sensor 72 (internal temperature detection unit), a workload detection unit 73, and a drive device 74 as the control system for the image forming unit 20.

[0064] As described above, the image creating unit 20 is an element that forms an image in the image forming apparatus 100. The drive device 74 is an element that drives the image creating unit 20. The drive device 74 applies a driving force to the photosensitive drum 40, the developing roller 29a, the charging roller 18, the primary transfer roller 62, and the like, among the components of the image creating unit 20 illustrated in Fig. 2, for example. The drive device 74 has, for example, a motor as a drive source, and transmits power to each component of the image creating unit 20 via a power transmission mechanism such as a gear system.

[0065] The control unit 70 controls the operation of the drive device. The control unit 70 outputs a control command to the drive device 74 based on various information related to the image forming apparatus 100 and the image forming unit 20 acquired from an external temperature sensor 71, an internal temperature sensor 72, and a workload detection unit 73, as shown in FIG. 4, for example, thereby controlling the operation of the image forming unit 20.

[0066] The external temperature sensor 71 detects the temperature outside the image forming apparatus 100. The external temperature sensor 71 is disposed in the external housing of the image forming apparatus 100, for example.

[0067] The internal temperature sensor 72 detects the temperature inside the image forming apparatus 100. The internal temperature sensor 72 is disposed, for example, in the gaps between the various elements of the image forming unit 20 illustrated in FIG.

[0068] Workload detection unit 73 detects the workload of image creation unit 20. In this embodiment, the "workload" includes information related to the number of pages continuously printed by image creation unit 20. Workload detection unit 73 is installed at an arbitrary position inside image forming apparatus 100 where the workload of image creation unit 20 can be detected.

[0069] Particularly in this embodiment, the control unit 70 can control the imaging unit 20 to switch between two print operation restriction states based on the temperature outside the image forming apparatus 100 (print operation restriction mode control).

[0070] More specifically, when the temperature detected by the external temperature sensor 71 is below a predetermined "environmental temperature threshold TA," the control unit 70 transitions to a "first printing operation restricted state" based on the workload (i.e., the number of pages continuously printed by the image creating unit 20) detected by the workload detection unit 73. The first printing operation restricted state temporarily stops driving the image creating unit 20 by the drive device 74 for a predetermined period of time every time the workload reaches a predetermined workload threshold (i.e., every time a predetermined number of pages continuously printed is reached).

[0071] On the other hand, when the temperature detected by the external temperature sensor 71 is equal to or higher than the environmental temperature threshold value TA, the control unit 70 transitions to a "second printing operation restricted state" based on the internal temperature detected by the internal temperature sensor 72. The second printing operation restricted state is an intermittent operation in which, when the internal temperature is higher than a predetermined internal temperature threshold value, a pause state in which the driving of the image forming unit 20 by the driving device 74 is stopped and a printing state in which the image forming unit 20 is driven are repeated until the internal temperature falls below the internal temperature threshold value.

[0072] The control unit 70 can be configured as, for example, a part of a controller 910 that controls the overall operation of the image forming apparatus 100. Alternatively, the control unit 70 can be configured as a control board having a CPU, RAM, etc., that is provided in the image forming apparatus 100 separately from the controller 910. Each function of the control unit 70 described above is realized by loading predetermined computer software onto hardware such as the CPU and RAM, operating various hardware such as a communication module, input device, and output device under the control of the CPU, and reading and writing data from and to the RAM and auxiliary storage device.

[0073] In addition, each function of the control unit 70 that is realized by the CPU executing a predetermined program can also be configured to be realized by an electronic circuit such as an ASIC (application specific integrated circuit) or an FPGA (field programmable gate array).

[0074] Note that, as the "workload of the imaging unit 20" detected by the workload detection unit 73 and used by the control unit 70 to determine whether to transition to the "first print operation restricted state", information other than the number of continuously printed pages may be used. For example, information such as the continuous operation time of the drive device 74 of the imaging unit 20 or the travel distance of the imaging unit 20 may be used.

[0075] <Explanation of Print Operation Restriction Mode Control> The differences between a conventional printing operation restriction mode and the printing operation restriction mode of this embodiment will be described with reference to FIGS. 5 to 7. FIG.

[0076] << Conventional printing operation restriction mode >> Fig. 5 is a sequence diagram of an example of a conventional print operation restriction mode. The vertical axis of Fig. 5 indicates the temperature T (°C) of the image forming unit 20, and the horizontal axis indicates the printing time s (seconds) of the image forming unit 20. Graph A, which is a solid line in Fig. 5, indicates the actual temperature inside the image forming unit 20. Graph B, which is a dotted line, indicates the temperature measured by the internal temperature sensor 72. Fig. 5 illustrates the transition of the internal temperature when the temperature outside the image forming apparatus 100 (ambient temperature) is 32°C.

[0077] When the temperature of the imaging unit 20 (development bearings, etc.) becomes high, problems such as toner adhesion may occur. In order to prevent such problems from occurring, in the conventional method, an internal temperature sensor 72 is provided to detect the temperature of the imaging unit 20, and when the value of the internal temperature sensor 72 exceeds a threshold value, a print operation restriction mode is entered in which the printing operation is restricted.

[0078] As shown in FIG. 5, in order to prevent the temperature of the image forming unit 20 from exceeding a predetermined upper limit temperature Td (e.g., 45°C), during printing time s1, when the detected temperature detected by the internal temperature sensor 72 exceeds a predetermined first threshold value T1 (e.g., 40°C lower than Td), the printing operation restriction mode is entered.

[0079] In the print operation restriction mode, an intermittent operation (e.g., 25-second stop, 20-page printing) is performed in which a pause state in which the driving of the image forming unit 20 is stopped and a print state are repeated, reducing productivity and preventing the temperature of the image forming unit from rising. Note that in this embodiment, such a print operation restriction mode using a conventional method is called the "second print operation restriction state" as described above.

[0080] In the example of Figure 5, by continuing the print operation restriction mode during the section from printing time s1 to s2, the temperature of the image forming unit 20 decreases, and when the value of the internal temperature sensor 72 reaches a predetermined second threshold value T2 (e.g., 39°C, which is lower than the first threshold value T1) during printing time s2, the print operation restriction mode is released and normal continuous printing is resumed.

[0081] Here, there is a discrepancy between the temperature of the imaging unit 20 (graph A) that is actually to be controlled and the value of the internal temperature sensor 72 (graph B), and the amount of discrepancy fluctuates depending on the environmental temperature, which is a problem in performing optimal control in the conventional method. As shown in FIG. 5, in a high-temperature environment where the environmental temperature exceeds 30° C., as shown in behavior A1 immediately before the printing time s1 in graph A, the printing operation restriction mode is entered in a state where the temperature rise gradient of the imaging unit 20 is large. In the printing operation restriction mode state, the driving of the imaging unit 20 stops during the pause, so the temperature of the imaging unit 20 drops, but when printing is resumed after a certain time, the temperature of the imaging unit 20 rises again because the temperature of the imaging unit 20 is in a state where the temperature rise gradient is large. This operation continues, and the temperature of the imaging unit 20 and the temperature detected by the internal temperature sensor 72 gradually decrease, and when it is determined that the detected temperature has decreased to a temperature that is within a margin of Td, the printing operation restriction mode is released.

[0082] <<Issues with conventional methods>> Fig. 6 is a sequence diagram of another example of a conventional print operation restriction mode. Fig. 6 shows the actual temperature (graph A) of the image forming unit 20 and the detected temperature (graph B) of the internal temperature sensor 72 during continuous printing in a low temperature environment (e.g., 28°C) that is lower than that of Fig. 5. The vertical and horizontal axes of Fig. 6 are the same as those of Fig. 5.

[0083] The temperature of the imaging unit 20 rises due to heat generated by its own rotation, and the actual temperature A of the imaging unit does not differ greatly in the gradient of temperature rise due to the difference in the environmental temperature between Fig. 5 and Fig. 6. Meanwhile, the internal temperature sensor 72 is not directly attached to the rotating body of the imaging unit 20, and detects the ambient temperature in the vicinity of the imaging unit 20. Therefore, when the environmental temperature drops as in the example of Fig. 6, the detected temperature B of the internal temperature sensor 72 is influenced by the drop in the environmental temperature, and the temperature rise becomes gradual. As a result, in the low temperature environment shown in Fig. 6, the difference between the actual temperature A of the imaging unit 20 and the detected temperature B of the internal temperature sensor 72 becomes larger, as shown in area B1 in Fig. 6, for example, compared to the high temperature environment shown in Fig. 5.

[0084] In the 32°C environment (high temperature environment) shown in Fig. 5, when the temperature of the imaging unit 20 rises to Td during printing time S1, the internal temperature rises to the first threshold T1 and the printing operation restriction mode is entered. However, as shown in Fig. 6, in the 28°C environment (low temperature environment), when the temperature of the imaging unit 20 reaches Td (printing time s3), the internal temperature has not risen to the first threshold T1, and the printing operation restriction mode cannot be entered. This is the first problem with the conventional method.

[0085] Due to the first problem, when the internal temperature rises to the first threshold T1 during printing time s4, the temperature of the imaging unit 20 exceeds Td, and the risk of defects due to toner aggregation and the like increases. To solve this, it is necessary to lower the temperature threshold setting of the first threshold T1, but since the first threshold T1 has the same value even in a 32°C environment (high-temperature environment in FIG. 5), this also leads to a deterioration in productivity in a high-temperature environment such as a 32°C environment. In other words, if the first threshold T1 is lowered in the high-temperature environment of FIG. 5, the printing operation restriction mode will be entered at a timing earlier than printing time S1. In this case, the actual temperature of the imaging unit 20 is sufficiently lower than Td, and the printing operation restriction mode will be executed even in an area where it is not necessary to execute the mode, and the printing amount will be reduced accordingly, resulting in a deterioration in productivity.

[0086] In addition, when the printing operation limit mode is entered in a 28°C environment (low temperature environment), the temperature rise gradient of the imaging unit 20 is smaller than that of the high temperature environment shown in FIG. 5, as shown by behavior A2 immediately before printing time s4 in graph A. In other words, the printing operation limit mode is entered in a state close to saturation. When the driving of the imaging unit 20 is reduced during a pause in the printing operation limit mode, the temperature of the imaging unit 20 drops. When printing is resumed after a certain time, the temperature of the imaging unit 20 rises again, but the imaging unit 20 is at a temperature close to the saturation temperature, and the outside air temperature is low, so the cooling efficiency of the fan is high, so the amount of temperature rise after resumption is small. As a result, in the low temperature environment of FIG. 6, the amount of temperature drop is larger in the section from printing time s4 to s5 during the printing operation limit mode compared to the high temperature environment of FIG. 5. Since the imaging unit 20 itself becomes a heat source by being driven, the temperature drops rapidly when the driving is reduced.

[0087] On the other hand, since the internal temperature sensor 72 is not attached to the rotating body, it is disposed near the imaging unit 20 and detects the ambient temperature of the imaging unit 20. Therefore, during the printing time s4 to s5 in the printing operation restriction mode, the drop in the temperature detected by the internal temperature sensor 72 is smaller than the actual temperature of the imaging unit 20. As a result, even if the temperature of the imaging unit 20 itself has sufficiently dropped during the printing operation restriction mode and the printing operation restriction mode can be released, the temperature detected by the internal temperature sensor 72 does not drop, and the printing operation restriction mode continues until it drops to the second threshold value T2 at printing time s5. This is the second problem with the conventional method.

[0088] The second problem reduces user productivity. In other words, in the low-temperature environment of FIG. 6, it is possible to switch from the print operation restriction mode back to normal printing earlier than printing time s5, but the print operation restriction mode is implemented even in sections where it is not necessary, and the print volume is reduced accordingly, resulting in reduced productivity. Thus, the conventional method has the problem of not being able to optimize print productivity.

[0089] <<Printing Operation Restriction Mode Control of this Embodiment>> Fig. 7 is a sequence diagram of the print operation limit mode of this embodiment. The specifications of the graph shown in Fig. 7 are the same as those in Fig. 5 and Fig. 6. Fig. 7 also shows the transition of a low temperature environment similar to that in Fig. 6.

[0090] This embodiment is characterized in that when the environmental temperature is low, a temporary pause is set based on the number of sheets continued to be printed (or information related to the amount of work, such as the duration), rather than on the temperature detected by the internal temperature sensor 72 (graph B). For example, as in printing time s6 in FIG. 7, even if the temperature detected by the internal temperature sensor 72 has not risen to the first threshold value T1, a pause of a predetermined time (e.g., 30 seconds) is set when, for example, 600 pages (corresponding to 10 minutes) have been continuously printed. Note that this new printing operation restriction mode used in this embodiment is called the "first printing operation restriction state" in this embodiment, as described above.

[0091] As described above, when the environmental temperature is low, the temperature drop gradient of the imaging unit 20 when the driving of the imaging unit 20 is stopped is large, so that even if pausing and printing are not repeated continuously in a short span, a temporary pause of about 30 seconds can sufficiently lower the actual temperature of the imaging unit 20 as shown by the behavior A3 immediately after the printing time s6 in graph A, and the subsequent printing time can be extended. By introducing this operation, it is possible to suppress the temperature rise of the imaging unit 20 more than when printing is continued continuously (dotted line part A4 after time s6 in graph A in FIG. 7), and it is possible to keep the actual temperature of the imaging unit 20 at a temperature Td or lower at which problems such as toner adhesion are likely to occur. As a result, it is no longer necessary to switch to the printing operation restriction mode, which significantly reduces productivity by repeating pausing and printing in a short span as in the past, and it is possible to minimize the decrease in user productivity while preventing problems such as toner adhesion caused by high internal temperatures.

[0092] In this embodiment, there are two printing operation limit modes depending on the environmental temperature, and in the first limit mode, a temporary pause is provided depending on information related to the workload of the printing operation, such as the number of sheets to be printed or the duration of printing. In other words, based on the change in the environmental temperature outside the image forming apparatus 100, a printing operation limit mode control is implemented to switch between the two printing operation limit states, the "first printing operation limit state" and the "second printing operation limit state", described above. When the environmental temperature is relatively high, the second printing operation limit state is implemented based on the temperature detected by the internal temperature sensor 72. On the other hand, when the environmental temperature is relatively low, the first printing operation limit state is implemented based on the workload detected by the workload detection unit 73 (i.e., information such as the number of pages printed continuously by the image forming unit 20). In this embodiment, such printing operation limit mode control can prevent unnecessary implementation of the printing operation limit mode due to the change in the environmental temperature, and can minimize the decrease in productivity.

[0093] <Flowchart of Printing Operation State Restriction Mode Control> Fig. 8 is a flowchart of the print operation limit mode control of this embodiment. In Fig. 8, the number of pages printed continuously is applied as the workload of the imaging unit 20 detected by the workload detection unit 73. Also, a 30°C environment is applied as the high temperature environment, a 28°C environment is applied as the low temperature environment, and the environmental temperature threshold value TA is 29°C. A series of processes in the flowchart shown in Fig. 8 are performed by the control unit.

[0094] In step S101, when a printing operation is started, a print page counter is reset and the counter is incremented for each printed page.

[0095] In step S102, the printing operation restriction state to be implemented is selected based on the environmental temperature. Specifically, it is determined whether the environmental temperature is equal to or lower than a predetermined environmental temperature threshold value TA. In this example, the environmental temperature threshold value TA is set to 29°C. If the environmental temperature is equal to or lower than TA ("Yes" in S102), it is a 28°C environment (low temperature environment), so the process proceeds to S103 to determine whether to transition to a first printing operation restriction state. On the other hand, if the environmental temperature is higher than TA ("No" in S102), it is a 30°C environment (high temperature environment), so the process proceeds to S106 to determine whether to transition to a second printing operation restriction state.

[0096] In step S103, it is determined whether the number of continuously printed pages is within a predetermined number of pages Pt. The control unit 70 detects the number of continuously printed pages by, for example, referring to the print page counter mentioned in step S101. If the number of continuously printed pages is within the predetermined number of pages Pt ("Yes" in S103), the process proceeds to step S104, where continuous printing continues. On the other hand, if the number of continuously printed pages is greater than the predetermined number of pages Pt ("No" in S103), the process proceeds to step S105, where a first printing operation restriction state is executed. The predetermined number of pages Pt corresponds to a "workload threshold", and for example, if Pt=600 pages and the execution time of the first printing operation restriction state is set to 30 seconds, a 30-second pause is executed every 600 pages in the continuous printing state.

[0097] When the process of step S104 is completed, the process proceeds to step S110, and when the process of step S105 is completed, the process returns to step S101.

[0098] In an environment where TA is higher than 29°C, a transition to a second print operation restricted state is determined in S106. Specifically, it is determined whether the internal temperature is equal to or lower than a predetermined first threshold T1. The control unit 70 uses the temperature information input from the internal temperature sensor 72 as the internal temperature. In this example, the first threshold T1 is set to 40°C. If the internal temperature exceeds T1=40°C ("No" in step S106), the process proceeds to step S108 and the state transitions to the second print operation restricted state, which continues until the internal temperature falls below a second threshold T2 (for example, set to 39°C, which is lower than the first threshold) ("Yes" in step S109).

[0099] If the internal temperature is equal to or lower than the first threshold T1 ("Yes" in step S106), the process proceeds to step S107 to continue the continuous printing. After the continuous printing process in steps S104 and S107, or if the internal temperature is equal to or lower than the second threshold T2 while in the second print operation restricted state in step S109 ("Yes" in S109), it is determined in step S110 whether the print job is complete. If the print job is complete ("Yes" in S110), the printing operation ends. If the print job is not complete ("No" in S110), the process returns to step S102.

[0100] Similarly, if the internal temperature becomes higher than the second threshold T2 during the second print operation restricted state in step S109 ("No" in S109), it is determined in step S111 whether the print job is completed. If the print job is completed ("Yes" in S111), the printing operation ends. If the print job is not completed ("No" in S111), the process returns to step S108.

[0101] The number of printable sheets per unit time in the first printing operation restricted state is greater than the number of printable sheets per unit time in the second printing operation restricted state. In this way, by being able to switch the printing operation restricted state according to the environment, it is possible to realize optimization of the rise in temperature inside the machine and productivity.

[0102] As described above, the information related to the workload of the imaging unit 20 detected by the workload detection unit 73 may be something other than the number of continuously printed pages. For example, information such as the continuous operation time of the drive device 74 that drives the imaging unit (imaging unit 20) or the travel distance of the imaging unit can be used. In this case, similar control can be performed by replacing "printed pages" in steps S101 and S103 in Fig. 8 with "continuous operation time (e.g., 10 minutes)" or "travel distance".

[0103] FIG. 9 is a first modified flowchart of the print operation restriction mode control.

[0104] In the flowchart of Fig. 9, step S1021 is added between steps S101 and S102 of the flowchart of Fig. 8, in which it is determined whether the environmental temperature is equal to or lower than a predetermined lower limit value TB. The lower limit value TB is set to a value lower than the environmental temperature threshold value TA, which is a determination index for switching the print operation restriction mode (see Fig. 7).

[0105] If the environmental temperature is equal to or lower than the lower limit TB (S1021: Yes), the process proceeds to step S110, and the print operation limit mode switching determination in step S102 is not performed. If the environmental temperature is higher than the lower limit TB (S1021: No), the process proceeds to step S102.

[0106] In other words, in the flowchart of Figure 9, even if the temperature detected by the external temperature sensor 71 is below the environmental temperature threshold value TA, the control unit 70 does not transition to the first printing operation restriction state if the temperature detected by the external temperature sensor 71 is below a predetermined lower limit value TB that is lower than the environmental temperature threshold value TA.

[0107] If the environmental temperature is low enough, the imaging unit temperature will not exceed Td (=45°C) even if continuous printing is performed for a long period of time. Therefore, in this situation, there is no need to impose the first printing operation restriction. By setting a lower limit TB for the environmental temperature and implementing the first printing operation restriction only when the environmental temperature is between the environmental temperature threshold value TA and the lower limit TB, it is possible to more effectively prevent a decrease in productivity.

[0108] To summarize, in the process of the flowchart in FIG. 9, the allocation of print operation restrictions according to the environmental temperature is as shown in the following table. (1) Environmental temperature T < TB: No print operation restrictions are imposed in any case. (2) TB ≤ T < TA: If the conditions are met, the first print operation restriction is imposed. (3) TA ≤ T: If the conditions are met, the second print operation restriction is imposed.

[0109] FIG. 10 is a second modification example of the flowchart of the print operation restriction mode control.

[0110] In the flowchart of FIG. 10, between steps S103 and S105 of the flowcharts of FIGS. 8 and 9, a determination as to whether the temperature inside the machine is less than or equal to a predetermined first threshold value T1 is added as step S1031. The set value of the first threshold value T1 is the same as that in step S106.

[0111] When the temperature inside the machine is less than or equal to the first threshold value T1 (Yes in S1031), the process moves to step S110, and the first print operation restriction mode of step S105 is not executed. When the temperature inside the machine is higher than the first threshold value T1 (No in S1031), the process proceeds to step S105.

[0112] That is, in the flowchart of FIG. 10, even when the temperature detected by the outside temperature sensor 71 is less than the environmental temperature threshold value TA, if the temperature inside the machine detected by the inside temperature sensor 72 is less than or equal to the first threshold value T1, the control unit 70 does not shift to the first print operation restriction state.

[0113] In the process of the flowcharts in Figures 8 and 9, when the outside air temperature is between TB and TA, the first printing operation restriction occurs every 600 pages. The printing operation restriction only needs to prevent the imaging unit temperature from exceeding the target Td, so there is no need to activate it from the early stages of continuous printing when the temperature inside the machine is low. Therefore, in the flowchart in Figure 10, a judgment is added in step S1031 to impose a restriction on the temperature inside the machine, so that the first printing operation restriction is only performed when the temperature inside the machine is high. This makes it possible to more effectively prevent a decrease in productivity.

[0114] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Any design modifications made by a person skilled in the art to these specific examples are also included within the scope of the present disclosure as long as they have the features of the present disclosure. The elements of each of the above-mentioned specific examples and their arrangements, conditions, shapes, etc. are not limited to those exemplified and can be changed as appropriate. The combination of each of the elements of each of the above-mentioned specific examples can be changed as appropriate as long as no technical contradiction occurs. [Explanation of symbols]

[0115] 100 Image forming device 20 Imaging section 70 Control section 71 External temperature sensor (external temperature detection section) 72 Internal temperature sensor (internal temperature detection section) 73 Work volume detection unit 74 Drive Unit TA Ambient Temperature Threshold TB Lower Limit Pt Number of pages (threshold) T1 First Threshold T2 Second Threshold [Prior art documents] [Patent documents]

[0116] [Patent Document 1] JP 2014-157266 A

Claims

1. an image forming unit for forming an image; A drive device that drives the imaging unit; An outside temperature detection unit that detects the temperature outside the device; an interior temperature detection unit that detects the temperature inside the aircraft; a workload detection unit that detects a workload of the image forming unit; A control unit that controls the operation of the drive device; having The control unit is when the temperature detected by the external temperature detection unit is less than a predetermined environmental temperature threshold, transitioning to a first printing operation restricted state based on the workload detected by the workload detection unit, the first printing operation restricted state temporarily suspending driving of the image forming unit by the drive device for a predetermined period of time every time the workload reaches a predetermined workload threshold; The control unit is When the temperature detected by the external temperature detection unit is equal to or higher than the environmental temperature threshold, the printer transitions to a second printing operation restricted state based on the internal temperature detected by the internal temperature detection unit, and the second printing operation restricted state performs an intermittent operation in which a pause state in which the driving of the image forming unit by the driving device is stopped and a printing state in which the image forming unit is driven are repeated until the internal temperature falls below a second threshold lower than the first threshold when the internal temperature is higher than a predetermined first threshold. Image forming device.

2. the amount of work includes the number of pages continuously printed by the image forming unit; The image forming apparatus according to claim 1 .

3. The amount of work includes a continuous operation time of the drive device.

3. The image forming apparatus according to claim 1 or 2.

4. the number of printable sheets per unit time in the first print operation restricted state is greater than the number of printable sheets per unit time in the second print operation restricted state; The image forming apparatus according to any one of claims 1 to 3.

5. the control unit does not transition to the first print operation restricted state when the temperature detected by the outside-machine temperature detection unit is less than the environmental temperature threshold value even if the temperature detected by the outside-machine temperature detection unit is less than a predetermined lower limit value that is lower than the environmental temperature threshold value. The image forming apparatus according to any one of claims 1 to 4.

6. the control unit does not transition to the first print operation restriction state when the inside-machine temperature detected by the inside-machine temperature detection unit is equal to or lower than the first threshold value even if the temperature detected by the outside-machine temperature detection unit is lower than the environmental temperature threshold value. The image forming apparatus according to any one of claims 1 to 4.

Images