JP2007010789A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of efficiently performing processing by starting a job with low priority when the job becomes processable or performing immediate switching to a job with high priority when the job becomes processable when memory capacity is restricted and the job with low priority is short in a preparation period than the job with high priority. <P>SOLUTION: The image forming apparatus is provided with: a document read section 3 which requires a first period to return from a standby state and get ready to read a document; a printing data reception section which receives external printing data; an image formation section 11 which requires a second period to return from a standby state and get ready to print; and an image formation control section 9 which controls operations of the document read section and image formation section. The image formation control section 9 performs control to receive print data which are nearly as much as data which can be printed from the end of the second period to the end of the first period when returning from a standby state and then print the print data after the end of the second period. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus including a document reading unit and an image forming unit.

  2. Description of the Related Art An image forming apparatus is known that includes a document reading unit that reads a document, a print data receiving unit that receives print data, and an image forming unit that prints a read document image or an image based on received print data. For example, it is a digital multi-function peripheral having both copier and printer functions.

  Some of these image forming apparatuses require a preparation operation before starting document reading and printing, and require time for that. For example, if the document reading unit is of a type that scans a document, the scanning unit is moved to a reference position, or the lighting (pre-lighting) is performed to stabilize the light quantity of an exposure lamp that irradiates the document. Some require a shading correction operation to make the reading density in the main scanning direction uniform. If the print image forming unit is an electrophotographic image forming unit, for example, the fixing heater for fixing the formed image on the image forming member is warmed up to a predetermined temperature, or the initial stage of the electrophotographic process Some of them need to be processed. Alternatively, in the case of an ink-jet image forming unit, there is one that requires an initialization process in which the ink head unit is cleaned and moved to a predetermined position.

  The contents of the preparatory operation are generally different after the power is turned on and during standby. Further, it varies depending on whether or not the state is transited to the power saving state during standby. From the viewpoint of efficient processing, it is preferable that the time from the standby state to the document reading or printing start is short. However, from the viewpoint of power saving, it is preferable to suppress power consumption of each part as much as possible during standby, and the requirements of both are often contradictory. In view of this, several efforts have been made to achieve both power saving and shortening the total waiting time required for the preparation operation.

  For example, in an apparatus that normally takes the most time for fixing warm-up, the time required to raise the temperature of the fixing unit to a predetermined temperature is obtained, and it is required to increase the current light amount of the exposure lamp (copy lamp) to the predetermined light amount. If the time required to increase the rotation speed of the polygon mirror to the predetermined speed is longer than the time required for warm-up, the power supplied to the motor that drives the copy lamp or polygon mirror is increased, and the warm-up A device that controls the rotation of the copy lamp and the polygon motor to be in a predetermined state by the end is known (see, for example, Patent Document 1).

As described above, the time required for the preparation operation differs between processing functions different from each other, for example, copying and printer. On the other hand, different processing functions have different priorities. In general, since copying is performed by a user in front of a multifunction peripheral and waiting for copying to be completed, it is required to perform processing more quickly than a printer and has a high priority. However, the high-priority copy preparation operation is not always shorter than a lower-priority printer. For example,
In recent years, a device with a short warm-up time has been put into practical use due to technical progress of fixing devices and toners. On the other hand, halogen lamps have conventionally been the mainstream as exposure lamps, but cold cathode tubes have come to be widely used as the sensitivity of document reading image sensors has improved. The cold cathode tube has an advantage that it has a higher light emission rate than a halogen lamp and a uniform distribution of light emission luminance. However, the time required for the amount of emitted light to stabilize after lighting is longer than that of the halogen lamp. Therefore, depending on the configuration of the image forming apparatus, there is a case where the time from the standby state until printing becomes possible is shorter than the time until reading becomes possible.
JP 2003-302874 A

As described above, when a preparation operation is started in response to a request for a job of a different type, a low priority job may be processed first. For example, in an image forming apparatus in which the preparation period of an image forming unit is shorter than that of a document reading unit, when both a print job and a copy job are requested, a print job using only the image forming unit can be processed first. Thereafter, a copy job using both the document reading unit and the image forming unit can be processed. Therefore, if the printing of the received data is started when the print job can be processed and then the copying is started when the original can be read, the total work time can be shortened, which is efficient. However, the user who wants to make a copy waits in front of the image forming apparatus until printing is completed. To cope with this, the multi-function peripheral has a job switching function that can stop printing and start copying by a user operation. However, some popular machines do not have an image memory that can hold print data of print processing interrupted inside the image forming apparatus due to cost restrictions. In such a multi-function peripheral, copying cannot be started until print data up to at least the next page break is received and printed. After requesting job switching, the user waits for a long time until copying can be started.
Even in an image forming apparatus with a limited image memory, there is a demand for a technique that can immediately switch jobs when a job with a high priority can be processed.

  The present invention has been made in consideration of such circumstances. When the memory capacity is limited and the low-priority job has a shorter preparation period than the high-priority job, the low-priority job is Provided is an image forming apparatus capable of starting a job when it can be processed, and immediately switching to a job with a higher priority when a job with a higher priority can be processed, thereby performing efficient processing. Is.

According to the present invention, a document reading unit that takes a first period until the document can be read after returning from the standby state, a print data receiving unit for receiving print data from the outside, and returning from the standby state to enable printing. An image forming unit that requires a second period until the end, and an image forming control unit that controls operations of the document reading unit and the image forming unit,
The image forming control unit performs control to receive print data that can be printed from the end of the second period to the end of the first period upon returning from the standby state, and to print after the end of the second period. An image forming apparatus is provided.

  In the image forming apparatus according to the present invention, when the image forming control unit returns from the standby state, the image forming control unit receives print data that can be printed from the end of the second period to the end of the first period, and prints after the end of the second period. Since the warm-up is completed until pre-lighting is completed, print data that can be printed is received by the end of pre-lighting and printing is performed. When pre-lighting is finished, copying is started immediately. Can do. Therefore, when both the printing and copying requests are received during standby or preparation operation, the printing and copying processes can be performed efficiently.

  Here, the document reading request is, for example, that the user requests the start of copying by pressing a predetermined key on the operation panel provided in the image forming apparatus, and the image forming apparatus detects that the key is pressed. It may be. The document reading request is a request for processing performed using the document reading unit, and may be copy processing. However, the document reading request is not limited to this, and for example, processing of a scanner that reads a document image and stores image data in the host Or processing such as FAX transmission.

  The image reading unit may be in a pre-lit state of the exposure lamp during the first period, but is not limited to this. For example, the image reading unit is in a state of preparing the document reading device other than the pre-lit state such as shading correction. There may be a pre-lighting state and a preparatory state combining other preparatory processes. In addition, the image forming unit may be in a warm-up state of fixing during the second period, but is not limited to this. For example, the initialization state of the electrophotographic photosensitive member or the toner density adjustment of the developer In addition to warm-up, the image forming apparatus may be in a state of preparation, or may be in a preparation state in which the warm-up state and other preparation processes are combined.

A reception control unit that controls reception of the print data may be further provided, and the reception control unit may control the reception of the print data received during the standby state or the first period to be equal to or less than a predetermined number of pages. In this way, by limiting the number of pages of print data to be received, it is possible to receive print data that can be printed after the end of the second period and before the end of the first period.
The reception control unit acquires the data size for each page of the print data and the paper size before starting the print data reception from the host PC. The reception control unit has a print time characteristic table for the data size and the paper size in advance, and can estimate the print time for each page with reference to the print time characteristic table. Further, the estimated time for each page is sequentially added from the first page, and compared with the time until the end of the first period after the end of the second period, printing can be performed after the end of the second period and before the end of the first period. Determine the number of sheets. In this way, after determining the printable sheet number, the reception control unit designates the receivable sheet number to the host PC.

  The document reading unit includes an exposure lamp that irradiates the document, the image forming unit includes a fixing unit that heats the image forming member and fixes an image on the image forming member, and the document reading unit includes a first It may be in a pre-lighting state in which the light quantity of the exposure lamp is stabilized during the period, and the image forming unit is in a warm-up state in which the fixing unit is warmed to a predetermined temperature during the second period.

  Furthermore, a fixing temperature detecting unit for detecting the temperature of the fixing unit, a warm-up characteristic table for giving a first predicted time until the end of the warm-up state for each temperature of the fixing unit, and a light amount detection for detecting the light amount of the exposure lamp And a pre-lighting characteristic table that gives a second predicted time until the pre-lighting state ends for each detected light amount, and the reception control unit refers to the warm-up characteristic table at the detected temperature of the fixing unit The first predicted time is obtained, the second predicted time is obtained by referring to the pre-lighting characteristic table with the detected light amount of the exposure lamp, and the print data to be received based on the first predicted time and the second predicted time The number of pages may be determined.

  In this way, it is possible to accurately determine the number of pages of print data from the first predicted time based on the detected fixing temperature and the second predicted time based on the detected amount of exposure lamp light. Accordingly, it is possible to appropriately determine the number of pages to which printing is completed before the end of the first period according to the state of the apparatus at that time.

  Furthermore, the reception control unit may obtain the first predicted time and the second predicted time to update the number of pages of print data to be received each time print data for each page is received. In this way, since the number of pages is updated every time print data for each page is received, the number of pages can be determined more accurately reflecting the progress of the preparation operation.

  The reading request detection unit detects the presence or absence of a document reading request during the first period and during the printing, and the first period when the image formation control unit detects the document reading request by the reading request detection unit. Alternatively, it may be controlled to start reading a document after the printing is completed. In this way, when a document reading request is made during the first period or during the printing, the document reading is started after the end of the first period or after the end of the printing. Switching to is performed quickly.

  Further, the document reading unit has a reading failure detection unit that detects the presence or absence of a failure in the document reading unit, and the image forming unit has a printing failure detection unit that detects the presence or absence of a failure in the image forming unit, The image formation control unit controls the heater to warm up and start image formation based on the print data when the operation of the image reading unit is normal even when a failure is detected in the operation of the document reading unit. May be. In this way, the printing process is performed even when the original reading unit has an operation failure.

  Hereinafter, the present invention will be described in more detail with reference to the drawings. The following description will provide a better understanding of the present invention. In addition, this invention is not limited by the following description.

≪Mechanical structure≫
FIG. 2 is an explanatory diagram showing a configuration example of the image forming apparatus of the present invention. As shown in FIG. 2, the image forming apparatus according to this embodiment is roughly composed of a document reading unit 3, an image forming unit 11, and a sheet conveying unit which is another part.

  The document reading unit irradiates the document with light and generates image data corresponding to the image of the document from the reflected light. The image forming unit forms a visible image based on the image data generated by the document reading unit, and prints the visible image on a predetermined transfer sheet (sheet). The sheet conveying unit supplies the sheet to the image forming unit and discharges the printed sheet.

  First, details of the document reading unit will be described. The document reading unit has a document table 101 made of transparent glass on the upper surface. A scanner optical system is disposed below the document table 101. The scanner optical system includes an exposure lamp 102, a reflecting mirror 103, an imaging lens 104, and a photoelectric conversion element (CCD) 105. The exposure lamp 102 is a light source 102 for irradiating a document placed on the document table 101 with light. The reflecting mirror 103 guides the reflected light from the document to the imaging lens 104 and the CCD 105 as indicated by a straight line in the drawing, for example. The CCD 105 receives reflected light imaged by the imaging lens 104 and generates an electrical signal corresponding to the reflected light as an image signal.

  The generated electrical signal is input to a CCD control board (not shown). The CCD control board is equipped with an A / D conversion circuit for A / D converting a signal from the CCD to obtain pixel data. Pixel data obtained by A / D conversion is further input to a control board (not shown) arranged in the image forming unit. The control board is equipped with an image memory for storing pixel data and an image processing circuit for processing the pixel data and outputting it as print data to the LSU 117 described later. The control board includes a microcomputer for controlling the document reading unit and the image forming unit, a ROM for storing a control program executed by the microcomputer, signals from sensors and switches of each unit of the document reading unit and the image forming unit. A receiving input circuit and an output circuit for driving a load such as a motor and a solenoid are mounted. Further, a receiving circuit for receiving print data from an external host is mounted.

  On the right side of the document table 101, a shading correction white plate 106 is arranged. The shading white plate 106 is irradiated by the exposure lamp 102, the reflected light is read by the CCD 105, and the signal from the CCD is A / D converted. The microcomputer of the control board can detect the light quantity of the exposure lamp 102 based on the A / D converted CCD signal. Further, it is possible to correct the sensitivity variation of each pixel in the main scanning direction of the CCD and the illuminance unevenness of the exposure lamp 102.

  Next, details of the image forming unit and the sheet conveying unit will be described. The image forming unit includes a photosensitive roller 111, a charging unit 112, a developing unit 113, a transfer charger 114, a fixing roller 115, a fixing heater 119, a cleaning device 116, a laser scanning unit (LSU) 117 (not shown), and a fixing paper detection switch. I have. The photosensitive roller 111 is a drum-shaped photosensitive roller 111, and is driven to rotate so that a sheet conveyed through a main conveyance path 121, which will be described later, is in contact with the surface of the photosensitive roller 111 at the same speed. The charging unit 112 charges the surface of the photosensitive roller 111 to a predetermined potential. The LSU 117 scans and exposes the surface of the charged photosensitive roller 111 by scanning a laser beam in a direction parallel to the rotation axis of the photosensitive roller 111, thereby exposing the surface of the photosensitive roller 111 from the document reading unit. An electrostatic latent image corresponding to the image signal of the read original is formed. The developing unit 113 develops the electrostatic latent image formed on the surface of the photosensitive roller 111 using the LSU 117 with the developing roller 118, and forms a toner image (a visible image) on the surface of the photosensitive roller 111. . The transfer charger 114 transfers the toner image on the photosensitive roller 111 to a sheet. The fixing heater 119 is disposed inside the fixing roller 115 and heats the fixing roller 115. The fixing roller 115 heat-fixes the unfixed toner image transferred to the printed sheet on the sheet. A fixing temperature detection sensor 120 made of a thermistor is disposed on the surface of the fixing roller, and detects the surface temperature of the fixing roller 115. The signal of the fixing temperature detection sensor 120 is connected to the input circuit of the control board, and provides information on the surface temperature of the fixing roller 115 to the microcomputer of the control board. The fixing heater 119 is connected to the output circuit of the control board, and the heater on / off is controlled by the microcomputer of the control board. The fixing paper detection switch detects that the sheet has passed the fixing roller 115. The cleaning device 116 removes the toner remaining on the surface of the photosensitive roller 111 after the toner image is transferred to the sheet.

  The sheet conveyance unit includes a main conveyance path 121, a sub conveyance path 122, a fixed sheet feeding cassette 123, a pickup roller 124, a registration roller 125, a guide member 126, a sheet discharge port 127, a sheet discharge roller 128, and a conveyance roller 129. A pre-registration detection switch is provided. The fixed paper feed cassette 123 is for storing sheets for printing. The pick-up roller 124 is a half-moon-shaped roller for outputting sheets one by one from the fixed sheet feeding cassette 123. The pre-registration detection switch is for detecting that the sheet conveyed by the pickup roller 124 has passed a predetermined position on the main conveyance path 121 and outputting a predetermined detection signal. The registration roller 125 temporarily holds the sheet conveyed through the main conveyance path 121. The sheet has a function of transporting the sheet with good timing in accordance with the rotation of the photosensitive roller 111 so that the leading edge of the toner image on the photosensitive roller 111 can be transferred in synchronization with the leading edge of the sheet. That is, the registration roller 125 conveys the sheet based on the detection signal output by the pre-registration detection switch so that the leading edge of the toner image on the photosensitive roller 111 is synchronized with the leading edge of the printing range on the sheet.

  A discharge roller 128 is provided in the vicinity of the discharge port 127, and allows the sheet discharged from the fixing roller 115 to be fixedly fed to the first discharge tray 130 or the second discharge tray 131 (below the document reading unit). It is a roller for discharging to a movable tray disposed at the top of the paper cassette 123. The paper discharge roller 128 has a function as a back surface printing mechanism together with the guide member 126 and the sub transport path 122. That is, in normal single-sided printing, the guide member 126 is arranged in the B direction in FIG. 2 and can convey the sheet from the main conveyance path 121 to the paper discharge roller 128. On the other hand, when printing on both sides of the sheet, when printing on the first side of the sheet is completed and the trailing edge of the sheet is discharged from the main conveyance path 121, the guide member 126 is rotated in the A direction to discharge the sheet. The sheet reversely fed from the roller 128 is disposed so as to be guided to the sub conveyance path 122. The paper discharge roller 128 rotates in the forward direction (the direction in which the sheet is output from the paper discharge port 127) until the trailing edge of the sheet output from the fixing roller 115 passes through the guide member 126, and then in the reverse direction. Rotate. Thus, the sheet passes through the guide member 126 and is conveyed to the sub-conveying path 122, and is conveyed again to the registration roller 125 by the conveying roller 129, and printing is performed on the second surface (back surface).

≪Functional configuration≫
FIG. 1 is a block diagram showing an example of a functional configuration of an image forming apparatus according to the present invention. In FIG. 1, the image forming apparatus 1 includes a document reading unit 3, a print data receiving unit 5, a reading request detecting unit 7, an image forming control unit 9, and an image forming unit 11. More preferably, a reception control unit 19 is provided.

  The document reading unit 3 is a block for reading an image of a document, and also shows a mechanism portion corresponding to FIG. The print data receiving unit 5 is a block that receives print data from an external host computer 27. This block is realized by the microcomputer performing the receiving process according to the control program stored in the ROM using the print data receiving circuit portion of the control board already described. It is. The read request detection unit 7 is a block that detects that the user has requested the start of copying, and corresponds to, for example, a copy start key provided in the operation panel of the image forming apparatus. The image forming control unit 9 is a block for controlling the operation of the image forming apparatus 1. Of the control board, an input / output circuit for controlling the operation of the image forming apparatus 1 is used. This block is realized by controlling the operation of the image forming apparatus 1 according to the control program. The image forming unit 11 is a block that performs printing.

  In this embodiment, the document reading unit 3 includes an exposure lamp 102 using a cold cathode tube, a light amount detection unit 15, and a reading failure detection unit 17. The exposure lamp 102 is also shown in FIG. 2, and is a lamp that irradiates a document. The light quantity detection unit 15 is lit with the exposure lamp 102 positioned immediately below the shading correction white plate 106, and the microcomputer of the control board described above is stored in the ROM so as to read the light guided to the CCD 105 in FIG. This is realized by executing a control program. The reading failure detection unit 17 is realized by detecting a failure by the microcomputer of the control board judging signals from sensors provided in the respective units of the document reading unit 3 according to a control program stored in the ROM. Block.

Further, the image forming unit 11 includes a fixing heater 119, a fixing temperature detection unit 23, and a printing failure detection unit 25. The fixing heater 119 is also shown in FIG. 2 and is used for fixing the image formed on the printing member by heating the fixing roller 115. The fixing temperature detection unit 23 is realized by reading a signal from the fixing temperature detection sensor 120 arranged on the surface of the fixing roller 115 according to a control program stored in the ROM and converting the signal into a temperature by the microcomputer of the control board. Block. Further, the printing failure detection unit 25 is realized by detecting a failure by the microcomputer of the control board judging a signal from a sensor provided in each unit of the document reading unit 3 according to a control program stored in the ROM. Block.
The reception control unit 19 is a block realized when the microcomputer of the control board controls reception according to a control program stored in the ROM.

≪Flowchart≫
(Embodiment 1)
In this embodiment, operation control of the document reading unit and the image forming unit when the time from the end of the warm-up state to the end of the pre-lighting state is a predetermined time will be described.

  3 and 4 are flowcharts showing an example of a processing procedure executed by the microcomputer of the control board in accordance with a control program stored in the ROM. As shown in FIG. 3, when the standby state continues for a predetermined time, the image forming control unit 9 shifts the image forming apparatus to the shutdown state (step S101). In the shutdown state, the fixing heater 119 and the exposure lamp 102 are not energized. When the print data receiving unit 5 receives print data from the host 27 in the shutdown state, the print data receiving unit 5 notifies the image formation control unit 9 of the reception of the print data as a return request (step S103).

  In response to the return request, the image formation control unit 9 turns on the fixing heater 119 to start warm-up, and turns on the exposure lamp 102 to start pre-lighting. In addition, other initialization operations of the image forming unit 11 and the document reading unit 3 are started. The other initialization operation is, for example, an initialization operation of an electrophotographic process for the image forming unit 11, and an operation for moving the exposure lamp and the reflecting mirror to an initial position for the document reading unit 3. Further, the image formation control unit 9 determines whether or not the energization return request is a request for a print job (step S105).

  If the return request is not due to reception of print data, for example, if the copy request is detected by the read request detector 7 by operating a key on the operation panel (not shown), the routine proceeds to step S139. The image formation control unit 9 confirms that the fixing roller 115 has reached a predetermined temperature (step S139), and confirms that the light quantity of the exposure lamp is stable (step S141), and then executes a copy process (step S141). Step S143). When the end of the copy process is completed (step S145), the image forming control unit 9 shifts to a standby state, that is, an online state waiting for receiving print data (step S137). Thereafter, when the standby state continues for a predetermined time, the image forming control unit 9 shifts the image forming apparatus to the shutdown state (step S101).

On the other hand, if the determination result in step S105 is a print job request, the routine proceeds to step S107. Then, the image formation control unit 9 acquires information on the print job to be processed (print data information) from the received content at the beginning of the series of print data (step S107), and the number of printable sheets based on the acquired information Is set (step S109).
Here, the reason why the image forming control unit 9 sets the printable number of sheets after acquiring the print data information is that the data size of the data to be printed out is determined even if the time difference between the fixing temperature stabilization time and the lamp light quantity stabilization time is determined. This is because the printing time per sheet changes. The image formation control unit 9 sets the number of printable sheets from the acquired print data information in consideration of the data size of the print data.

  Then, the print data for the set number of printable sheets is requested and the reception of the print data is continued (step S111). When the print data for the requested number of sheets is received (step S113), the image forming control unit 9 checks whether or not the fixing roller 115 has reached a predetermined temperature. If the predetermined temperature has not been reached, the warm-up is completed. (Step S115). Then, after the warm-up is completed, a print job is executed (step S117). After the print job is completed (step S119), the image formation control unit 9 checks whether a copy reservation has been made (step S121). Copy reservation is performed when the user presses the copy start key during the warm-up state corresponding to the return request, the pre-lit state, and the print job of the received print data, and the reading request detection unit 7 detects the key press. Made.

  If the copy reservation has been made, the routine proceeds to step S123, waits for the light quantity of the copy lamp to stabilize and the pre-lighting state to end, and then executes the reserved copy job (step S125). After the copy job is completed (step S127), if there is subsequent print data, the print data is accepted (step S129). Then, the routine proceeds to step S131.

  On the other hand, if there is no copy reservation in step S121, the routine proceeds to step S122 and accepts subsequent print data. In step S131, the image formation control unit 9 checks whether or not there remains anything to be printed. If there is data to be printed, the remaining print data is received (step S133), and printing is performed (step S135).

  When all the printing is completed, the process shifts to a standby state, that is, an online state waiting for print data reception (step S137). After that, when the standby state continues for a predetermined time, the image forming control unit 9 shifts the image forming apparatus to the shutdown state (step S101).

(Embodiment 2)
In this embodiment, the operation control of the document reading unit and the image forming unit in the case of obtaining the time from the end of the warm-up state to the end of the pre-lighting state when returning from the shutdown will be described.

  5 and 6 are flowcharts showing an example of a processing procedure executed by the microcomputer of the control board in accordance with the control program stored in the ROM in this embodiment. Steps S201 to S207 in FIG. 5 correspond to steps having the same last two digits in Steps S101 to S107 in FIG. Further, steps S211 to 245 in FIGS. 5 and 6 correspond to steps having the same last two digits in steps S111 to 145 in FIG. Steps S209, 210, 251, and 253 that are different from those in FIGS.

  When the print job request is returned from the shutdown, the image formation control unit 9 calculates the number of printable sheets in step S209. The specific calculation procedure is as follows.

  The image forming control unit 9 holds a characteristic of the fixing temperature with respect to the warm-up time (warm-up characteristic table). The warm-up characteristic table may be, for example, a fixed value stored in the ROM as a standard characteristic, but is not limited to this, and the measurement result for each image forming apparatus is stored in the nonvolatile RAM. There may be. By referring to the warm-up characteristic table, it is possible to obtain an estimated time from the fixing temperature detected by the fixing temperature detector 23 to the end of the warm-up.

  If the calculated number of printable sheets is 0 (step S210), the printing process is not performed, and the routine proceeds to step S221 to determine whether there is a copy reservation.

  Further, when printing for the number of printable sheets calculated first is finished and a reserved copy is started but the pre-lighting state is not finished (step S223), the routine proceeds to step S251 and the pre-lighting state is reached. It is determined whether or not the subsequent print data should be printed while waiting for the end of. First, it is determined whether there is subsequent print data (step S251). If there is no subsequent print data, the routine proceeds to step S223 and waits for the pre-lighting state to end. When there is subsequent print data, the image formation control unit 9 predicts again the time until the pre-lighting state ends (step S253). Specifically, it is as follows.

  The image formation control unit 9 holds a characteristic of the amount of reflected light with respect to the pre-lighting time (pre-lighting characteristic table). The pre-lighting characteristic table may be, for example, a fixed value stored in the ROM as a standard characteristic, or may be a result obtained by storing a measurement result for each image forming apparatus in a nonvolatile RAM. By referring to the pre-lighting characteristic table, it is possible to obtain an estimated time from the reflected light amount detected by the light amount detection unit 15 to the end of pre-lighting.

  After obtaining the predicted time until the pre-lighting state ends, the routine proceeds to step S209, and calculates the number of printable sheets in the time until the pre-lighting state ends. Since the warm-up has already been completed at this point, the image forming unit 11 may calculate the number of printable sheets on the assumption that printing can be started immediately after receiving the print data. If the calculated number of printable sheets is 1 or more, the host computer 27 is requested to print data for the number of printable sheets (step S211), and after reception (step S213), printing is performed (step S217).

(Embodiment 3)
In this embodiment, when returning from shutdown, in order to improve the accuracy of the predicted time from the end of the warm-up state to the end of the pre-lighting state, time prediction is performed every time print data for one page is received The operation control of the original reading unit and the image forming unit will be described.

  7 and 8 are flowcharts showing an example of a processing procedure executed by the microcomputer of the control board in accordance with the control program stored in the ROM in this embodiment. Steps S301 to S353 in FIGS. 7 and 8 correspond to steps having the same last two digits in steps S201 to S253 in FIGS. Steps S361 to 371, 381, 383, and 391 to 395 that are different from FIGS.

When the print job request is returned from the shutdown, the image formation control unit 9 receives the next page of received data in step S361 (step S361). Then, the printing time T0 ′ of the received print data is predicted (step S363). The predicted time T0 ′ is obtained as follows.
A specific method for obtaining T0 ′ is as follows. A table relating to printing time as a base is stored in advance in an electrically rewritable ROM. This table is a printing time table related to the paper size and the data size. Further, since the printing time increases correspondingly when the cassette position changes to the subsequent stage, the difference can be added by holding the cassette position distance and the conveyance speed.
When obtaining T0 ′, the paper size of the received print data and the print time based on the data size are estimated by referring to this table, and the paper due to the difference in the position of the paper cassette corresponding to the paper size is also input to the image forming unit. The delay time until transport is estimated by referring to this table.

When the predicted time T0 ′ is obtained, T0 ′ is added to the total printing time T0 of the print data that has already been received and the total printing time T0 is updated before calculating T0 ′ (step S365).
Next, the image formation control unit 9 obtains the time from the end of the warm-up state to the end of the pre-lighting state, that is, the estimated printable time T1 (step S367). Details of the process of calculating the predicted time T1 will be described later.

  After obtaining the predicted time T1, the image formation control unit 9 determines whether or not the total printing time T0 is equal to or longer than the printable predicted time T1 (step S369). If the total print time T0 is equal to or exceeds the printable predicted time T1, no further print data is received. In this case, the routine proceeds to S351, and the received print data is printed after the warm-up state is finished.

  On the other hand, when the time T0 is less than T1, it is determined whether or not the capacity for receiving the next page of print data remains, that is, whether or not the image memory becomes full when the next page of print data is received. (Step S371). If the memory is full, no more print data can be received, so the routine proceeds to step S315, where the received print data is printed after the warm-up state is completed. If the memory is not full, the routine proceeds to step S361, and further receives print data for the next page.

  Here, the process for obtaining the time T1 will be described. The image formation control unit 9 causes the exposure detection unit 15 to detect the light amount of the exposure lamp. Then, a predicted time T3 until the light amount of the exposure lamp is stabilized is calculated from the detected light amount (step S391). If T3 has already been calculated, the value of T3 is updated again. Next, the fixing temperature detector 23 detects the fixing temperature. Then, an estimated time T2 until the warm-up is completed is calculated from the detected fixing temperature (step S393). If T2 has already been calculated, the value of T2 is updated again.

Then, the time difference between T3 and T2 is calculated to obtain T1 (step S395).
FIG. 9 is an explanatory diagram showing the relationship between the printable predicted time T1, the predicted time T2 until the warm-up state ends, and the predicted time T3 until the pre-lighting state ends.

  Also, the image forming control unit 9 does not finish the pre-lighting state after completing the printing of the printable number of sheets predicted in step S317, and whether there is subsequent printing data while waiting for the start of the copy reservation. It is determined whether or not (step S351). If there is no subsequent print data, the routine proceeds to step S323 and waits for the pre-lighting state to end. If there is subsequent print data, the image formation control unit 9 receives the print data for the next page (step S381), prints the received page (step S383), and then proceeds to step S323, where the pre-lighting is performed again. Determine whether the state is finished.

  In addition to the embodiments described so far, it is obvious that various modifications can be made to the present invention. Such variations are not to be construed as not belonging to the features and scope of the invention. It will be apparent to those skilled in the art that such variations are intended to be included within the scope of the claims of this invention.

1 is a block diagram illustrating an example of a functional configuration of an image forming apparatus according to the present invention. It is explanatory drawing which shows the structural example of the image forming apparatus of this invention. It is a flowchart which shows an example of the process sequence which a microcomputer performs according to a control program. (Embodiment 1) It is a flowchart which shows an example of the process sequence which a microcomputer performs according to a control program. (Embodiment 1) It is a flowchart which shows an example from which the process procedure which a microcomputer performs according to a control program differs. (Embodiment 2) It is a flowchart which shows an example from which the process procedure which a microcomputer performs according to a control program differs. (Embodiment 2) It is a flowchart which shows another example of the process procedure which a microcomputer performs according to a control program. (Embodiment 3) It is a flowchart which shows another example of the process procedure which a microcomputer performs according to a control program. (Embodiment 3) It is explanatory drawing which shows the relationship of printable prediction time T1, prediction time T2 until completion | finish of a warm-up state, and prediction time T3 until completion | finish of a pre lighting state. (Embodiment 3)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 3 Document reading part 5 Print data receiving part 7 Reading request | requirement detection part 9 Image formation control part 11 Image formation part 15 Light quantity detection part 17 Reading fault detection part 19 Reception control part 23 Fixing temperature detection part 25 Printing fault detection part 27 Host computer 101 Document table 102 Exposure lamp 103 Reflector 104 Lens 105 Optical conversion element, CCD
106 Shading correction white plate 111 Photosensitive roller 112 Charging unit 113 Developing unit 114 Transfer charger 115 Fixing roller 116 Cleaning device 117 Laser scanning unit, LSU
118 Developing roller 119 Fixing heater 120 Fixing temperature detection sensor 121 Main transport circuit 122 Sub transport path 123 Fixed paper feed cassette 124 Pickup roller 125 Registration roller 126 Guide member 127 Paper discharge port 128 Paper discharge roller 129 Transport roller

Claims (7)

A document reading unit that takes a first period until it can read a document after returning from the standby state, a print data receiving unit that receives print data from the outside, and a first step before returning from the standby state and enabling printing An image forming unit that requires two periods, and an image forming control unit that controls operations of the document reading unit and the image forming unit,
The image forming control unit performs control to receive print data that can be printed from the end of the second period to the end of the first period upon returning from the standby state, and to print after the end of the second period. An image forming apparatus.   2. The reception control unit for controlling reception of print data, wherein the reception control unit controls reception of print data received in a standby state or during the first period to be equal to or less than a predetermined number of pages. Image forming apparatus.   The document reading unit includes an exposure lamp that irradiates the document, the image forming unit includes a fixing unit that heats the image forming member and fixes an image on the image forming member, and the document reading unit includes a first The image forming apparatus according to claim 1, wherein the image forming apparatus is in a pre-lighting state in which the light quantity of the exposure lamp is stabilized during the period, and the image forming unit is in a warm-up state in which the fixing unit is warmed to a predetermined temperature during the second period.   A fixing temperature detecting unit for detecting the temperature of the fixing unit, a warm-up characteristic table for giving a first predicted time until the end of the warm-up state for each temperature of the fixing unit, and a light amount detecting unit for detecting the light amount of the exposure lamp; A pre-lighting characteristic table that gives a second predicted time until the pre-lighting state ends for each detected light amount, and the reception control unit refers to the warm-up characteristic table based on the detected temperature of the fixing unit. 1 prediction time is obtained, the second prediction time is obtained by referring to the pre-lighting characteristic table with the detected light quantity of the exposure lamp, and the number of pages of print data to be received based on the first prediction time and the second prediction time The image forming apparatus according to claim 3, wherein:   The image formation according to claim 4, wherein the reception control unit obtains the first predicted time and the second predicted time and updates the number of pages of print data to be received each time print data of each page is received. apparatus.   The reading request detection unit detects the presence or absence of a document reading request during the first period and during printing, and the image formation control unit detects the document reading request by the reading request detection unit during the first period or The image forming apparatus according to claim 1, wherein control is performed so that document reading is started after the printing is completed.   The document reading unit includes a reading failure detection unit that detects whether there is a failure in the document reading unit, and the image forming unit includes a printing failure detection unit that detects whether there is a failure in the image forming unit, The formation control unit controls to start image formation based on print data by warming up the heater when the operation of the image forming unit is normal even when a failure is detected in the operation of the document reading unit. The image forming apparatus according to 1.

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