Image forming device

Abstract

To provide an image forming apparatus that shortens first printout time while preventing overflow of waste toner.SOLUTION: An image forming apparatus is used which has: a process cartridge including an image carrier, a developing roller that forms a toner image on the image carrier and is in contact with the image carrier, recovery means that recovers a residual toner on the image carrier, and storage means that stores the residual toner; control means that causes the process cartridge to start print preparation and causes the process cartridge to start a print operation; and image processing means that performs preparation processing for image data, issues an instruction to start the print preparation to the control means, and instructs the control means to start the print operation after the preparation processing. When the print preparation is completed and the instruction to start the print operation is output, the control means causes the process cartridge to start the print operation. The image forming apparatus has means that detects the integrated amount of recovered residual toner. When the integrated amount of recovered residual toner is equal to or more than a threshold, the control means delays the start of the print preparation compared with when the integrated amount of recovered residual toner is less than the threshold.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] For users of image forming devices, the first printout time (FPOT), which is the time from issuing a print command to ejecting a sheet of paper with an image formed on it, is best to keep it as short as possible. FPOT is determined by the time it takes for the controller of the image forming device to prepare image data (image data preparation process), the engine control unit of the image forming device to perform preparatory operations to start image formation (print preparation operation), and the printing operation to form an image on paper.

[0003] To shorten this FPOT, there is a method of starting image formation preparation operations simultaneously with the start of image data preparation processing, and performing image data preparation processing and print preparation operations in parallel (hereinafter referred to as preparation parallel operation).

[0004] Patent Document 1 proposes a method in which the difference between the elapsed time from the start of image formation preparatory operations to the start of image formation and a predetermined time is defined as excess time, and whether or not to perform preparatory parallel operations is selected based on the value of the accumulated excess time.The proposed method can prevent unnecessary rotation of components such as the fixing unit, which would shorten their lifespan, when there are many print jobs in which the time required for image data preparation processing is longer than the time required for image formation preparatory operations. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-228334 Summary of the Invention [Problem to be solved by the invention]

[0006] While the image forming device is operating in a printable state, in addition to the toner image formed based on image data, a small amount of toner (fog toner) adheres to the non-image forming areas on the photosensitive drum. The toner that adheres to the photosensitive drum but is not transferred to paper is scraped off by a cleaning blade provided in the cartridge as waste toner and collected in a waste toner container.

[0007] The amount of waste toner generated varies depending on the content of the image data, the state of the toner image based on that image data, and the amount of fog toner that depends on the rotation time of the image forming device. Therefore, if the amount of waste toner generated is greater than the amount of toner transferred to paper, the waste toner container will overflow before the cartridge reaches the end of its life.

[0008] In other words, in a process cartridge-type image forming apparatus, a process cartridge is known to have a waste toner container in addition to a photosensitive drum and a developing unit. In a process cartridge with such a configuration, it may not be possible to clear the collected waste toner from the waste toner container due to device configuration or cost constraints. In this case, if the waste toner container becomes full, the waste toner container will overflow, making the entire process cartridge unusable before the process cartridge reaches the end of its life due to deterioration of the cartridge components.

[0009] In particular, if preparatory parallel operation is performed to shorten FPOT and excess rotation time increases, more waste toner is generated, increasing the risk of the waste toner container overflowing. On the other hand, if whether to perform preparatory parallel operation to prevent waste toner overflow is determined based on the accumulated value of excess time as described in Patent Document 1, preparatory parallel operation will be limited regardless of the status of waste toner collection in the waste toner container, and opportunities to shorten FPOT will be limited.

[0010] The present invention has been made in view of the above-mentioned problems, and has an object to provide an image forming apparatus that can reduce the first printout time while preventing waste toner from overflowing. [Means for solving the problem]

[0011] The present invention employs the following configuration: a process cartridge including: an image carrier configured to form an electrostatic latent image on its surface in accordance with image data; a developing roller that supplies toner to the image carrier and develops the electrostatic latent image to form a toner image on the image carrier, the developing roller being in contact with the image carrier; recovery means that recovers residual toner, which is the toner that remains without being transferred from the image carrier; and storage means that stores the recovered residual toner; a control means for causing the process cartridge to start preparation for printing and for causing the process cartridge that has completed preparation for printing to start a printing operation; an image processing means for performing a preparatory process for the image data, which instructs the control means to start the print preparation, and after the preparatory process is completed, instructs the control means to start the print operation; and the control means causes the process cartridge to start the printing operation when the print preparation of the process cartridge is completed and an instruction to start the printing operation is output from the image processing means, a collected amount detecting means for detecting an accumulated collected amount of the residual toner stored in the storing means; The image forming apparatus is characterized in that, when the control means receives an instruction to start the printing preparation from the image processing means, it compares the accumulated recovered amount of the remaining toner detected by the recovered amount detection means with a predetermined threshold, and if the accumulated recovered amount is equal to or greater than the threshold, it delays the timing of starting the printing preparation compared to when the accumulated recovered amount is less than the threshold.

[0012] The present invention also employs the following configuration: An image forming apparatus that receives an external instruction to form an image on a recording material and discharges the image, a process cartridge including: an image carrier on whose surface an electrostatic latent image is formed in accordance with image data; a developing unit that supplies toner stored inside to the image carrier by a developing roller to develop the electrostatic latent image; a recovery unit that recovers residual toner, which is the toner that remains without being transferred from the image carrier to the recording material; and a storage unit that stores the recovered residual toner; When the printout time is defined as the time from receiving the external instruction to discharging the recording material on which the image is formed, the image forming apparatus is characterized in that, even when the same image is printed, the printout time when the amount of remaining toner stored in the storage means is a first amount is longer than the printout time when the amount of remaining toner stored in the storage means is a second amount that is less than the first amount. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide an image forming apparatus that can prevent waste toner from overflowing and reduce the first printout time. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic diagram of an image forming apparatus according to the present invention; [Figure 2] 1 is a block diagram showing a system configuration of an image forming apparatus according to the present invention; [Figure 3A] 4 is a timing chart showing a printing operation according to the present invention. [Figure 3B] 4 is a timing chart showing a printing operation according to the present invention. [Figure 3C] 4 is a timing chart showing a printing operation according to the present invention. [Figure 4] 6 is a flowchart for determining the start of a print preparation operation in the first embodiment. [Figure 5] 10 is a flowchart for determining the start of a print preparation operation in the second embodiment. [Figure 6] 10 is a flowchart for determining the start of a print preparation operation in the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] The following describes in detail, by way of example, the mode for carrying out the present invention with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, and relative positions of the components described in the embodiments may be changed as appropriate depending on the configuration and various conditions of the device to which the invention is applied. In other words, it is not intended that the scope of the present invention be limited to the following embodiments.

[0016] Example 1 [Overall configuration of image forming device] 1 is a cross-sectional view of an image forming apparatus according to this embodiment. In this embodiment, a laser beam printer 100 (hereinafter referred to as printer 100) is used as the image forming apparatus.

[0017] In FIG. 1, the photosensitive drum 122 (image carrier) is made of an organic photosensitive material or an amorphous silicon photosensitive material, and is rotated clockwise at a predetermined peripheral speed (process speed). The peripheral surface of the photosensitive drum 122 is uniformly charged to a predetermined polarity and potential by a charging roller 123. A laser beam output from the scanner 108 is then irradiated onto the charged surface, forming an electrostatic latent image on the photosensitive drum 122. The scanner 108 modulates (ON / OFF conversion) the laser beam in accordance with a time-series digital pixel signal under the control of the exposure control unit 208. The timing for starting scanning exposure in the sub-scanning direction is notified to the image signal generating device from the printer 100 by a sub-scanning direction synchronization signal.

[0018] Toner is stored inside the developing device 125 (developing means). A voltage is applied to the developing roller 121 together with the supply roller 124, and the developing roller 121 is rotated and driven in a state of uniform potential, thereby receiving a supply of toner from the supply roller 124. In this way, an electrostatic latent image formed on the surface of the photosensitive drum 122 corresponding to the target image is developed by the developing roller 121, which is in contact with the photosensitive drum 122 in a state where a voltage is applied. Here, it is assumed that the photosensitive drum 122 and the developing roller 121 of the present invention are always in contact with each other.

[0019] The printer 100 is provided with a paper feed tray 140 (paper feed port) on which paper P (recording material) is placed. Paper feed rollers 101 feed paper P from the paper feed tray 140. A registration sensor 105 detects that the paper P has reached a registration roller 104. The paper P is then fed toward a photosensitive drum 122 by the registration roller 104, and a mirror toner image of the photosensitive drum 122 side is formed on the paper P.

[0020] The transfer roller 106 transfers the toner image from the photosensitive drum 122 to the paper P by supplying a charge of the opposite polarity to the toner from the back surface (non-image forming surface) of the paper P. Residual toner that has not been transferred to the paper P and remains on the photosensitive drum 122 is scraped off by a cleaning blade 126 (collection means) and collected in a waste toner container 127 (storage means).

[0021] The paper P onto which the toner image has been transferred is separated from the photosensitive drum 122 and sent to the fixing device 130. The fixing unit 130 is made up of a thermistor 131, a heater 132, a fixing film 133, and a pressure roller 134. After the thermal fixing, the paper P is detected by a fixing paper discharge sensor 109 as having passed through the fixing unit 130 normally, and is then conveyed by a paper discharge roller 111 and discharged onto a paper discharge tray 112.

[0022] In the printer 100 of this embodiment, the photosensitive drum 122, charging roller 123, developing device 125, and waste toner container 127 are integrated into a process cartridge 150. The process cartridge 150 is configured to be detachable from the printer body.

[0023] [System configuration of image forming device] Next, the system configuration of the printer 100 will be described. Fig. 2 is a block diagram for explaining the system configuration of the printer 100. In Fig. 2, the printer 100 includes a controller unit 201 (image processing means) and an engine control unit 202 (control means). The controller unit 201 is capable of mutual communication with a host computer 200, which is an external device. The controller unit 201 is also capable of mutual communication with the engine control unit 202 via a video interface unit 203.

[0024] A host computer 200, which is an external device, transmits print conditions, image data of the print image, and a print command to a controller unit 201 of the printer 100. The controller unit 201 converts the image data received from the host computer 200 into exposure data required for the printer 100, and creates print reservation information for each sheet of paper based on the received print conditions. The print reservation information includes, for example, a paper feed port (such as paper feed tray 140) indicating the supply source of the paper P, the size of the paper P, the print mode, etc.

[0025] The controller unit 201 transmits a print reservation instruction for the page to the engine control unit 202 via the video interface unit 203, and when conversion from image data to exposure data is complete, transmits a print start instruction to the engine control unit 202. When the engine control unit 202 receives the print start instruction from the controller unit 201, it starts a print operation. The exposure data converted by the controller unit 201 is sent as a pixel signal to the exposure control unit 208 via the video interface unit 203, and is also sent to a pixel signal counting unit 224. The pixel signal counting unit 224 counts pixel signals during image formation and transmits the total count number for each page to the engine control unit 202 as a pixel signal value.

[0026] The drive control unit 209 drives and rotates each roller of the printer 100 using the main motor 204. The main motor 204 drives and rotates the paper feed roller 101, the registration roller 104, the photosensitive drum 122, the transfer roller 106, the pressure roller 134, and the paper discharge roller 111. The main motor 204 and the paper feed roller 101 are connected via a paper feed clutch 214, and when paper P is fed from the paper feed tray 140, the paper feed clutch 214 is engaged for a predetermined time to drive and rotate the paper feed roller 101.

[0027] In response to instructions from the engine control unit 202, the exposure control unit 208 rotates the scanner motor (not shown) provided in the scanner 108 and corrects the exposure amount, and controls the irradiation of laser light onto the photosensitive drum 122 based on exposure data received from the controller unit 201.

[0028] The high voltage control unit 210 controls the power supplies that apply DC voltages, ie, charging roller voltage 220, developing roller voltage 221, supply roller voltage 222, and transfer roller voltage 223, to the respective components within the printer 100, namely, the charging roller 123, developing roller 121, supply roller 124, and transfer roller 106.

[0029] The fixing control unit 211 detects the surface temperature of the heater 132 using the thermistor 131. The control unit 212 controls the power supply to the registration sensor 105 and the fixing / paper discharge sensor 109. The sensor input unit 212 acquires detection information from the registration sensor 105 and the fixing / paper discharge sensor 109 and outputs it to the engine control unit 202. The cartridge memory communication unit 215 communicates with a non-volatile cartridge memory (not shown) mounted on the cartridge via a two-wire serial system to read and write information.

[0030] The controller unit 201, engine control unit 202, video interface unit 203, pixel signal counting unit 224, exposure control unit 208, drive control unit 209, high voltage control unit 210, fixing control unit 211, and sensor input unit 212 may be realized by an information processing device having calculation resources such as a processor and memory, or a processing circuit such as an FPGA or ASIC. Each of the above components may be realized by a different information processing device or processing circuit, or a single information processing device or processing circuit may realize multiple components.

[0031] [Print preparation and image formation] A description will be given of the print preparation operation (preparatory operation for image forming operation) and print operation (image forming operation) of the printer 100 configured as described above. Figures 3A to 3C are timing charts showing the difference in each print operation depending on whether or not the preparation parallel operation is performed.

[0032] (When preparation parallel operation is not performed) 3A shows a case where the image data preparation process and the print preparation process are not performed in parallel. At t301, the host computer 200, which is an external device, starts image processing, and when the image processing is completed (t302), the host computer 200 notifies the controller unit 201 of a print instruction together with the image data.

[0033] When the controller unit 201 receives the print instruction, it starts the process of converting the image data into bitmap data, and when the image conversion process (image data preparation process) is completed (t303), it issues a print instruction to the engine control unit 202. The time required for this image conversion process is defined as T0a.

[0034] When an instruction to start a printing operation is received as preparation for printing, the engine control unit 202 drives the components of the process cartridge 150 so that the image forming apparatus can actually print. The engine control unit 202 starts the print preparation operation by driving the main motor 204 of the image forming apparatus to rotate the photosensitive drum 122 and starting the supply of toner to the photosensitive drum 122 by the developing roller 121. The engine control unit 202 drives the main motor 204, causes the charging roller 123 to uniformly charge the surface of the photosensitive drum 122, and causes the supply roller 124 to supply toner to the developing roller 121. The engine control unit 202 also causes the fixing control unit 211 to start supplying power to the fixing heater 132 as a start-up operation.

[0035] If an instruction to start a printing operation is issued, the image forming apparatus is ready to perform actual printing, and the print preparation operation is completed. In this embodiment, the print preparation operation is completed when a predetermined time (T1) has elapsed since the start of the fixing startup (t304). The engine control unit 202 drives the paper feed clutch 214 to feed paper P from the paper feed tray 140. At a predetermined timing after the leading edge of the paper P passes the registration sensor 105, the engine control unit 202 outputs a sub-scanning direction synchronization signal, which serves as the reference timing for outputting a digital pixel signal, to the controller unit 201 (t305).

[0036] As described above, the photosensitive drum 122 and the developing roller 121 are always in contact with each other. With this configuration, when the photosensitive drum 122 and the developing roller 121 are rotating, fog toner always adheres to the photosensitive drum 122. Here, fog toner refers to toner that adheres to areas of the photosensitive drum 122 that are not areas where an image is to be formed. Therefore, in this embodiment, fog toner adheres even during the print preparation operation while the photosensitive drum 122 is rotating. The fog toner thus generated is ultimately collected in the waste toner container 127, so if the amount of collected toner in the waste toner container 127 is large, the container may overflow due to the fog toner during the print preparation operation, so measures are required.

[0037] Based on the digital pixel signal received from the controller unit 201, the engine control unit 202 exposes the photosensitive drum 122 with the scanner 108 to form an electrostatic latent image, and causes the developing roller 121 to deposit toner onto the photosensitive drum 122. Thereafter, the engine control unit 202 applies a DC voltage of the opposite polarity to the toner image formed on the photosensitive drum 122 to the transfer roller 106, and transfers the toner image on the photosensitive drum 122 onto the paper P, which is then conveyed.

[0038] After the transmission of the image data is completed (t306), the paper P is peeled off from the photosensitive drum 122 and then transported to the fixing device 130. Then, the image on the paper P is fixed in the fixing nip formed by the fixing film 133 and the pressure roller 134, and the paper is discharged with the image side facing downwards onto the paper discharge tray 112 at the top of the main body via the paper discharge rollers 111.

[0039] The engine control unit 202 stops the print transport and the driving of the main motor 204 at the timing when the paper passes the paper discharge rollers 111 (t307). At this time, the driving time of the main motor 204 is the period from t303 to t307 (T2a), and the first printout time (FPOT, first time), which is the time from when a print command is issued until the paper on which an image is formed is discharged outside the device, is the period from t302 to t307 (T3a).

[0040] (When performing preparation parallel operations) 3B is a timing chart showing the printing operation when the preparatory parallel operation is performed. Hereinafter, the same processes as those in FIG. 3A will not be described. At t311, the host computer 200, which is an external device, starts image processing, and when the image processing is completed (t312), it notifies the controller unit 201 of a print instruction together with the image data.

[0041] When the controller unit 201 receives the print instruction, it notifies the engine control unit 202 of a pre-command indicating the start of print preparation, and starts the process of converting image data into bitmap data. The controller unit 201 issues a print instruction to the engine control unit 202 when the image conversion process is completed (t313). The time required for the image conversion process at this time is T0b, and in this case T0b=T0a.

[0042] 3A, and completes the print preparation after the predetermined time T1 has elapsed (t314). Since the engine control unit 202 has already received the print instruction at t313, which is earlier than t314, the engine control unit 202 drives the paper feed clutch 214 at t314 to feed paper P from the paper feed tray 140.

[0043] 3A, and after the controller unit 201 transmits image data (t315 to t316), the engine control unit 202 stops print transport and driving of the main motor 204 after the paper is ejected (t317). The driving time of the main motor 204 at this time is the period from t312 to t317 (T2b), which is equal to T2a. The FPOT time is the period from t312 to t317 (T3b), which is equal to T2b.

[0044] Comparing T3a, which is the FPOT in Figure 3A, with T3b, which is the FPOT in Figure 3B, we see that T3a is longer than T2a. Therefore, T3b is shorter than T3a. Therefore, it can be seen that FPOT is shorter in Figure 3B than in Figure 3A.

[0045] FIG. 3C shows the timing of the printing operation when the preparatory parallel operation is performed, as in FIG. 3B. 3B, differing from FIG. 3B in that it takes a longer time for the controller unit 201 to perform image development processing. At t321, the host computer 200, which is an external device, starts image processing, and when the image processing is completed (t322), it notifies the controller unit 201 of a print instruction together with the image data.

[0046] When the controller unit 201 receives a print instruction, it notifies the engine control unit 202 of a pre-command indicating the start of print preparation, and starts processing to convert image data into bitmap data. When the engine control unit 202 receives the pre-command, it starts print preparation in the same manner as described in Fig. 3A, and after a predetermined time T1 has elapsed, it determines that print preparation is complete (t323). At this point, the controller unit 201 is in the middle of image conversion processing and has not notified the engine control unit 202 of a print instruction, so the engine control unit 202 waits for notification of a print instruction without performing a paper feed operation (t323).

[0047] When the image development process is completed (t324), the controller unit 201 issues a print instruction to the engine control unit 202. The time required for the image development process at this time is T0c, and in this case, T0c is longer than T0b and shorter than the time T0a + T1. When the print instruction is received at t324, the engine control unit 202 drives the paper feed clutch 214 and feeds paper P from the paper feed tray 140.

[0048] The rest of the process is the same as in FIG. 3A. After the controller unit 201 transmits image data (t325 to t326), the engine control unit 202 stops print transport and driving of the main motor 204 after the paper is ejected (t327). The driving time of the main motor 204 at this time is the period (T2c) from t322 to t327, and T2c is longer than T2b and T2a. On the other hand, the FPOT time is the period (T3c) from t322 to t327, and T3c is equal to T2c. Also, the time T0c from the start of print preparation (t322) to paper feeding (t324) is shorter than the time (T0a+T1) in FIG. 3A, so FPOT can be shortened in FIG. 3C compared to FIG. 3A. On the other hand, the driving time of the main motor 204 increases by the amount of the surplus time compared to the cases of FIGS. 3A and 3B, and this increased time is the "waiting" time (T0c-T1) from t323 to t324.

[0049] [Detection of collected waste toner amount] Next, the detection of the amount of collected waste toner used in this embodiment will be described. The amount of collected waste toner is calculated by predicting the amount of waste toner due to fog toner generated during periods when no image formation is occurring (non-printing periods) and the amount of waste toner due to toner images and fog toner generated based on image data during periods when image formation is occurring (printing periods), and adding these amounts of waste toner together. This calculation process can be performed by an information processing device or processing circuit provided in the image forming apparatus 100, such as the engine control unit 202. In this case, the engine control unit 202 functions as a collected amount detection unit that detects the cumulative amount of collected remaining toner.

[0050] The printing period in Figure 3A is the period from t305 to t306. The non-printing period is the period from t303 to t307 when no printing is occurring while the main motor is driving, excluding t305 to t306. Similarly, the printing period in Figure 3B is the period from t315 to t316, and the non-printing period is the period from t312 to t317 when no printing is occurring while the main motor is driving. The printing period in Figure 3C is the period from t325 to t326, and the non-printing period is the period from t322 to t327 when no printing is occurring while the main motor is driving.

[0051] The amount of waste toner is predicted based on pixel signal values ​​sent from the pixel signal counting unit 224 to the engine control unit 202. During the printing period, of the amount of waste toner generated per page, the amount of waste toner (Wdt) due to the toner image based on image data is calculated using formula (1), and the amount of waste toner (Wbg) due to fog toner is calculated using formula (2).

[0052] Wdt=P×A …(1) where P and A are as follows: P: The number of pixels sent from the pixel signal counting unit 224 to the engine control unit 202. A: The amount of waste toner per pixel formed on the drum surface during the printing period. This is a predetermined value expressed in units of [% / pixel].

[0053] Wbg=(TP)×B …(2) where T and B are as follows: T: Total number of pixels during image formation. Determined by the drum rotation distance [mm] during the printing period and the number of pixels per predetermined drum rotation distance [pixels / mm]. B: Amount of waste toner during the printing period per pixel where no toner is formed on the drum surface. This is a predetermined value expressed in units of [% / pixel].

[0054] During non-printing periods, the amount of waste toner (Wrt) generated according to the rotation distance of the photosensitive drum is calculated using formula (3). Here, the unit of waste toner amount is %, with 100% being when the waste toner container is full. Since the toner on the photosensitive drum is mainly transferred to paper during printing periods and remains on the photosensitive drum without being transferred to paper during non-printing periods, the proportion of toner formed on the photosensitive drum that becomes waste toner is greater during non-printing periods than during printing periods.

[0055] Wrt = L × C … (3) where L and C are as follows: L: Drum rotation distance [mm]. C: Amount of waste toner during non-printing periods per distance on the drum surface where no toner is formed. This is a predetermined value, expressed in units of [% / mm].

[0056] From these amounts of waste toner, the amount of waste toner collected in the waste toner container per job (Wjob) is calculated using formula (4) each time a print job is executed, and the total amount of waste toner collected in the waste toner container (W) is calculated using formula (5). In other words, the amount of waste toner generated increases as the rotation distance (rotation time) per job increases. The value of this total amount of collected waste toner (W) is also recorded in non-volatile cartridge memory (not shown).

[0057] Wjob=Wdt+Wbg+Wrt …(4) W = W + Wjob …(5) However, W<=100[%]

[0058] In this embodiment, the method for calculating the amount of collected waste toner is not limited to the above example, and any method for calculating the amount of collected waste toner in waste toner container 127 may be used. For example, any method may be used, such as calculating the weight of the waste toner container or calculating the amount of collected toner in the container based on the electrostatic capacitance inside the toner container. Furthermore, the amount of waste toner may be calculated in any unit that can be compared with the toner capacity, and may be calculated not only by weight but also by volume, or may be based on the ratio of stored toner to the capacity.

[0059] [Judgement to start printing preparation] With the above-described configuration, an embodiment of the present invention will be described in which, after the controller unit 201 notifies the engine control unit 202 of a pre-command indicating the start of print preparation, the engine control unit 202 determines whether to start print preparation based on the amount of collected waste toner.

[0060] FIG. 4 shows the state in which the engine control unit 202 starts preparing for printing from a standby state waiting for the start of printing. This is the flow from when the engine control unit 202 receives a pre-command from the controller unit 201 (S401) to when the total amount of collected waste toner W is less than a threshold (S403). In this embodiment, the threshold is set to 80%. However, the threshold is not limited to this value; an appropriate value may be set depending on the device configuration, from the perspective of preventing toner overflow and reducing FPOT. If the total amount of collected waste toner W is less than the threshold, the engine control unit 202 immediately starts print preparation without delay from the timing of receiving the pre-command (S405) and terminates the process. Note that the term "immediately" here refers to a comparison with the case where print preparation is started after a delay from receiving the pre-command to prevent excessive rotation when the amount of collected toner is equal to or greater than the threshold. This does not exclude a slight delay from receiving the pre-command due to the specifications and performance range of the engine control unit. If the total amount of collected waste toner W is less than the threshold, the engine control unit does not need to consider toner overflow. Therefore, it can issue a command to start print preparation before the preparation process is completed and execute the preparation parallel operation. On the other hand, if the total amount of collected waste toner is equal to or greater than the threshold, it is more preferable to issue an instruction to start print preparation simultaneously with or after the preparation process is completed, taking into consideration the possibility of toner overflow.

[0061] On the other hand, if the total amount of collected waste toner W is equal to or greater than the threshold in S403, the engine control unit 202 waits to receive a print instruction notified by the controller unit 201 after image development is complete (S404), and when the print instruction is received, starts print preparation (S405) and ends the process. In other words, if the amount is equal to or greater than the threshold, the engine control unit 202 does not immediately instruct the start of print preparation, but rather issues an instruction to start print preparation after an interval. Note that the case where the controller unit 201 issues a print instruction without issuing a pre-command is the case shown in the timing chart of FIG. 3A, and in this case, print preparation is started via S401, S402, and S405 and the process ends.

[0062] As described above, in this embodiment, if the amount of collected waste toner is less than the threshold when the engine control unit 202 receives the pre-command, it starts print preparation to shorten the FPOT. On the other hand, if the amount of collected waste toner is equal to or greater than the threshold, it controls so that print preparation does not start when the pre-command is received, in order to eliminate excess rotation that generates waste toner, and prioritizes preventing overflow of the waste toner collection container. This makes it possible to shorten the FPOT when the cartridge is being used in a way that generates relatively little waste toner, and when waste toner generation is increasing, it prioritizes preventing overflow of waste toner over shortening the FPOT, allowing the cartridge to be used for a long time.

[0063] <Example 2> In the first embodiment, control was described for determining whether to start print preparation operation when a pre-command is received based on the total amount of collected waste toner in the waste toner container. In the second embodiment, control is described for determining the timing to start print preparation operation after receiving a pre-command based on the total amount of collected waste toner. This allows the balance between the priority of FPOT reduction and the priority of preventing waste toner overflow to be gradually changed based on the usage status of the cartridge as the total amount of collected waste toner increases. Below, explanations of the same configuration as in the first embodiment will be omitted.

[0064] [Judgement to start printing preparation] 5 shows the flow from the standby state in which the engine control unit 202 waits for the start of printing to the start of print preparation. When the engine control unit 202 receives a pre-command from the controller unit 201 (S501), it starts measuring the elapsed time since the pre-command was received (S503). Thereafter, it determines the print preparation start permitted time (Tstart) shown in Table 1 based on the total amount of collected waste toner W at that time. Note that a table showing the relationship in Table 1 may be stored, for example, in a storage device of an information processing device that functions as the engine control unit 202. Also, the relationship between the total amount of waste toner and Tstart is not limited to the table below. Also, the relationship may be stored in the form of a mathematical formula rather than a table. [Table 1]

[0065] When the time Tstart has elapsed (S505), the engine control unit 202 starts a print preparation operation (S507) and ends the process. While waiting for the time Tstart to elapse (S505), the engine control unit 202 waits for the reception of a print instruction notified by the controller unit 201 after image development is complete (S506), and when the print instruction is received, starts print preparation (S507) and ends the process.

[0066] Note that when the controller unit 201 issues a print instruction without issuing a pre-command, this is the case shown in the timing chart of FIG. 3(a), in which case printing preparation begins via S501, S502, and S507, and processing ends.

[0067] As described above, in this embodiment, the engine control unit 202 determines the time to start print preparation based on the amount of collected waste toner when it receives a pre-command. The smaller the amount of collected waste toner, the shorter the time; the greater the amount of collected waste toner, the longer the time. Then, after the determined time has elapsed, print preparation begins so as to shorten FPOT. The greater the amount of collected waste toner, the more control is exercised to delay the start of print preparation based on the reception of the pre-command, thereby prioritizing prevention of waste toner overflow in the waste toner collection container, thereby eliminating excess rotation that generates waste toner. This allows FPOT to be shortened when the cartridge is used in a state where waste toner generation is relatively low. When waste toner generation increases, the cartridge can be used for a longer period by prioritizing prevention of waste toner over FPOT reduction in multiple stages depending on the amount of waste toner generated.

[0068] Example 3 In the first embodiment, control was described for determining whether to start print preparation operation when a pre-command is received, depending on the total amount of collected waste toner in the waste toner container. In the third embodiment, control is described for determining whether to start print preparation operation after receiving a pre-command, taking into account not only the total amount of collected waste toner, but also the amount of toner consumed by the toner formed on the photosensitive drum. This allows the FPOT reduction control to continue when there is a high possibility that the toner before formation will run out before the waste toner container overflows. Below, explanations of the same configuration as in the first embodiment will be omitted.

[0069] [Toner consumption detection] The toner consumption detection used in this embodiment will now be described. Similar to the detection of the amount of collected waste toner in the first embodiment, the toner consumption detection is predicted based on pixel signal values ​​sent from the pixel signal counting unit 224 to the engine control unit 202. The toner consumption is calculated by predicting the amount of toner consumed by fog toner generated during periods when image formation is not performed and the amount of toner consumed by toner images and fog toner generated based on image data during periods when image formation is performed, and adding these toner consumption amounts together. This calculation process can be performed by an information processing device or processing circuit provided in the image forming apparatus 100, such as the engine control unit 202. In this case, the engine control unit 202 functions as a consumption detection unit that detects the cumulative amount of toner consumed.

[0070] The definitions of the printing period and non-printing period are the same as in Example 1. During the printing period, of the toner consumption amount occurring per page, the toner consumption amount (Cdt) due to the toner image based on the image data is calculated using formula (6), and the toner consumption amount (Cbg) due to the fog toner is calculated using formula (7).

[0071] Cdt=P×D …(6) where P and D are as follows: P: The number of pixels sent from the pixel signal counting unit 224 to the engine control unit 202 (same as equation (1)). D: Amount of toner consumed during the printing period per pixel formed with toner on the drum surface. This is a predetermined value, expressed in units of [% / pixel].

[0072] Cbg = (TP) × E … (7) where T and E are as follows: T: The total number of pixels during the image formation period. It is determined by the drum rotation distance [mm] during the printing period and the number of pixels per predetermined drum rotation distance [pixels / mm] (same as formula (2)). E: Amount of toner consumed during the printing period per pixel where toner is not formed on the drum surface. This is a predetermined value expressed in [% / pixel].

[0073] During the non-printing period, the toner consumption (Crt) that occurs according to the rotation distance of the photosensitive drum is calculated using formula (8). Here, the unit of toner consumption is %, and the state in which all the toner that can be formed on the photosensitive drum has been consumed is set to 100%.

[0074] Crt=L×F …(8) where L and F are as follows: L: drum rotation distance [mm] (same as formula (3)) F: Amount of toner consumed during non-printing periods per distance on the drum surface where no toner is formed. This is a predetermined value expressed in [% / mm].

[0075] From these toner consumption amounts, the toner consumption amount per job (Cjob) is calculated using formula (9) each time a print job is executed, and the total toner consumption amount (C) consumed since the cartridge was new is calculated using formula (10). The value of this total toner consumption amount (C) is also recorded in a non-volatile cartridge memory (not shown).

[0076] Cjob=Cdt+Cbg+Crt …(9) C=C+Cjob …(10) However, C<=100[%]

[0077] [Judgement of start of print preparation operation] 6 shows a flow from the standby state in which the engine control unit 202 waits for the start of printing to the start of print preparation. When the engine control unit 202 receives a pre-command from the controller unit 201 (S601), it determines whether the total amount of collected waste toner W at that time is less than a threshold value (X) (S603). In this embodiment, the threshold value X is set to 80%. If the total amount of collected waste toner W is less than the threshold value X, the engine control unit 202 starts print preparation at the timing of receiving the pre-command (S605) and ends the process. Note that the value of the threshold value X is not limited to this example.

[0078] On the other hand, if the total amount of collected waste toner W is equal to or greater than the threshold value X in step S603, the engine control unit 202 It is determined whether the total toner consumption amount C at that time is less than a threshold value (Y) (S606). In this embodiment, the threshold value Y is set to 90[%]. Note that the value of the threshold value Y (second threshold value) is not limited to this example.

[0079] If the threshold Y is exceeded, the engine control unit 202 starts print preparation at the timing of receiving the pre-command (S605) and ends the process. If the threshold Y is less than the threshold Y, the engine control unit 202 waits to receive a print instruction notified by the controller unit 201 after image development is complete (S604), and when the print instruction is received, starts print preparation (S605) and ends the process. Note that when the controller unit 201 issues a print instruction without issuing a pre-command, this is the case shown in the timing chart of Figure 3(a), and in this case, print preparation is started via S601, S602, and S605 and the process ends.

[0080] As described above, in this embodiment, if the amount of collected waste toner is less than a predetermined threshold and the total toner consumption is equal to or greater than a predetermined threshold when the engine control unit 202 receives a pre-command, it starts print preparation to shorten FPOT. In other cases, to eliminate excess rotation that generates waste toner, the engine control unit 202 controls the printer so that print preparation does not start when the pre-command is received, prioritizing preventing overflow of the waste toner collection container. This allows FPOT to be shortened when the cartridge is being used in a state where relatively little waste toner is generated or where usable toner is running low. When waste toner generation is increasing, preventing waste toner overflow is prioritized over shortening FPOT, allowing the cartridge to be used for a longer period of time.

[0081] In addition, in preventing waste toner overflow as in the third embodiment, it is possible to combine the determination of the print preparation start permitted time (Tstart) according to the amount of waste toner as in the second embodiment. In this case, it is preferable to determine Tstart according to the amount of waste toner before starting print preparation in step S605.

[0082] According to the above-described embodiments, the FPOT can be shortened when the cartridge is used in a state where waste toner generation is relatively small, and when waste toner generation is increasing, the cartridge can be used for a longer period by prioritizing prevention of waste toner overflow over shortening the FPOT. As a result, an image forming apparatus can be provided that shortens the FPOT while preventing waste toner overflow. Furthermore, considering that the period from when an image is formed in the FPOT to when the recording material is discharged is approximately constant, the present invention can provide an image forming apparatus that shortens the time from when a user instructs the printer to form an image while preventing waste toner overflow.

[0083] The present invention can also be understood as follows. That is, the cumulative amount of waste toner collected in the waste toner container is considered to be a first amount and a second amount that is smaller than the first amount. In this case, according to the present invention, even when printing the same image, the FPOT when the waste toner is the first amount will be longer than the FPOT when the waste toner is the second amount. [Explanation of symbols]

[0084] 100: Image forming apparatus, 122: Photosensitive drum, 125: Developing unit, 127: Waste toner container, 150: Process cartridge, 201: Controller unit, 202: Engine control unit

Claims

1. a process cartridge including: an image carrier configured to form an electrostatic latent image on its surface in accordance with image data; a developing roller that supplies toner to the image carrier and develops the electrostatic latent image to form a toner image on the image carrier, the developing roller being in contact with the image carrier; recovery means that recovers residual toner, which is the toner that remains without being transferred from the image carrier; and storage means that stores the recovered residual toner; a control means for causing the process cartridge to start preparation for printing and for causing the process cartridge that has completed preparation for printing to start a printing operation; an image processing means for performing a preparatory process for the image data, which instructs the control means to start the print preparation, and after the preparatory process is completed, instructs the control means to start the print operation; and the control means causes the process cartridge to start the printing operation when the print preparation of the process cartridge is completed and an instruction to start the printing operation is output from the image processing means, a collected amount detecting means for detecting an accumulated collected amount of the residual toner stored in the storing means; When the control means receives the instruction to start the print preparation from the image processing means, the control means compares the accumulated collected amount of the remaining toner detected by the collected amount detection means with a predetermined threshold, and when the accumulated collected amount is equal to or greater than the threshold, delays the timing of starting the print preparation compared to when the accumulated collected amount is less than the threshold. An image forming apparatus characterized by:

2. The image carrier and the developing roller are configured to be in constant contact with each other.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

3. The printing preparation includes rotating the image carrier.

3. The image forming apparatus according to claim 2, wherein the image forming apparatus is a recording medium.

4. When the accumulated collected amount of the remaining toner is less than the threshold value, the control unit issues an instruction to start the print preparation before the preparation process is completed.

4. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

5. When the accumulated collected amount of the remaining toner is equal to or greater than the threshold value, the control unit issues an instruction to start the print preparation simultaneously with or after the preparation process is completed.

5. The image forming apparatus according to claim 4.

6. When the cumulative collected amount of the remaining toner is equal to or greater than the threshold value, the control means delays the timing of causing the process cartridge to start the print preparation as the cumulative collected amount of the remaining toner increases.

6. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

7. The collected amount detecting means detects the integrated collected amount by calculating the amount of the remaining toner generated during a non-printing period when the image carrier is rotating and the printing operation is not performed, and the amount of the remaining toner generated during a printing period when the printing operation is performed.

7. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

8. The collected amount detecting means calculates the amount of the remaining toner during the non-printing period based on the rotation distance of the image carrier and the amount of the remaining toner per rotation distance, and The amount of the remaining toner is calculated based on the amount of the remaining toner based on the number of pixels in the area where the electrostatic latent image is formed on the image carrier and the amount of the remaining toner derived from fog toner generated during the printing period.

8. The image forming apparatus according to claim 7,

9. The toner supplying device further includes a consumption amount detecting means for detecting an accumulated consumption amount of the toner supplied to the image carrier, When the cumulative consumption amount of the toner detected by the consumption amount detection means exceeds a second threshold, the control means causes the process cartridge to immediately start the print preparation upon receiving a command to start the print preparation from the image processing means, regardless of the cumulative collected amount of the remaining toner detected by the collected amount detection means.

9. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

10. The consumption amount detection means detects the cumulative consumption amount by calculating the amount of toner consumed during a non-printing period when the image carrier is rotating and the printing operation is not performed, and the amount of toner consumed during a printing period when the printing operation is performed.

10. The image forming apparatus according to claim 9,

11. The consumption amount detection means calculates the amount of toner consumed during the non-printing period based on the rotation distance of the image carrier and the amount of toner consumed per rotation distance, and calculates the amount of toner consumed during the printing period based on the amount of toner consumed based on the number of pixels in an area where the electrostatic latent image is formed on the image carrier and the amount of toner consumed due to fog toner generated during the printing period.

11. The image forming apparatus according to claim 10.

12. An image forming apparatus that receives an external instruction to form an image on a recording material and discharges the image, a process cartridge including: an image carrier on whose surface an electrostatic latent image is formed in accordance with image data; a developing unit that supplies toner stored inside to the image carrier by a developing roller to develop the electrostatic latent image; a recovery unit that recovers residual toner, which is the toner that remains without being transferred from the image carrier to the recording material; and a storage unit that stores the recovered residual toner; When the time from receiving the external instruction to discharging the recording material on which the image is formed is defined as a printout time, even when the same image is printed, the printout time when the amount of the remaining toner contained in the container is a first amount is longer than the printout time when the amount of the remaining toner contained in the container is a second amount that is less than the first amount. An image forming apparatus characterized by:

Images