JP2010002529A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent generation of image deterioration or the like caused by increase of a temperature in an image forming device. <P>SOLUTION: This device includes a plurality of stages of paper feeding trays 21, 22, 23 arranged vertically; lifting parts 210, 220, 230 provided on the paper feeding trays 21-23, and lifting in the paper-loading state; an image forming part 10 positioned on the upper side of the paper feeding trays, for forming an image on the paper; a fixing part 12 provided on the image forming part 10; and a control part for controlling lifting operation of the lifting parts 210-230, and controlling paper feeding from the paper feeding trays 21-23. When using a tray other than the paper feeding tray 21 on the uppermost stage, the control part lowers the lifting part 210, and raises the lifting parts 220, 230 provided on the other paper feeding trays 22, 23 for preparation of paper feeding. When using the paper feeding tray 21 on the uppermost stage, the control part raises the lifting part 210 provided on the paper feeding tray on the uppermost stage for preparation of paper feeding. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that transfers an image formed based on image data onto a sheet fed from a sheet feeding tray and heat-fixes the image on the sheet.

In an image forming apparatus that forms an image based on image data, an image is transferred to a sheet and then heat-fixed, so that the temperature tends to remain in the apparatus. When the temperature inside the machine becomes high, problems such as toner solidification and image deterioration occur. In addition, the operating temperatures of motors, drivers, sensors, and the like provided in the image forming apparatus are fixed. If the temperature inside the apparatus rises, the operating temperatures of various electrical components may be exceeded, causing a problem. For this reason, in the conventional image forming apparatus, the temperature inside the apparatus is detected, and when the temperature inside the apparatus exceeds an allowable temperature, the internal temperature is forcibly cooled by a cooling fan or the like provided inside. Means for suppressing the rise is taken (for example, see Patent Document 1).
JP 2006-227559 A

  The above-described conventional image forming apparatus is designed to maintain the in-machine temperature within the allowable temperature range by controlling the operation of the cooling fan or the like while monitoring the in-machine temperature within the range where the ambient temperature is assumed. Yes. However, recently, due to the downsizing of the device, the gap between the fixing unit and the paper feed tray near the fixing unit is gradually reduced, and the paper loaded on the paper feed tray performs a heat retaining action to promote an increase in the in-machine temperature. It is easy to do. For this reason, if the ambient temperature exceeds the expected range or if continuous operation is performed more than expected, it will be difficult to maintain the in-machine temperature within the allowable temperature range even using a cooling fan, etc. There is a problem that will occur.

  The present invention has been made against the background of the above circumstances, and image formation that prevents the occurrence of image degradation by suppressing a rise in the internal temperature by securing a space between the fixing unit and the paper feed tray. An object is to provide an apparatus.

  In other words, the image forming apparatus according to the present invention is arranged in a plurality of stages on the top and bottom, and is provided with a paper feed tray that feeds paper by storing paper in each of the image forming apparatuses. An elevating unit, an image forming unit that is located above the paper feed tray and forms an image on a sheet based on image data, and is provided in the image forming unit, and heat-fixes the image formed on the sheet A fixing unit; and a control unit that controls a lifting operation of the lifting unit and a control unit that controls sheet feeding from the sheet feeding tray, the control unit being the uppermost sheet feeding tray of the sheet feeding trays When the other paper feed tray is used, the elevating part provided in the uppermost paper feed tray is lowered, and the elevating part provided in the other paper feed tray is raised for paper feed, The paper feed tray is used as the paper feed tray If, and wherein the increasing comprises a lifting unit provided in the paper feed tray uppermost in the sheet feeding.

  According to the image forming apparatus of the present invention, a plurality of stages are arranged on the upper and lower sides, and a paper feed tray that stores paper in each of the paper feed trays and is provided in the paper feed tray, and moves up and down by loading the paper. An elevating unit, an image forming unit that is located above the paper feed tray and forms an image on a sheet based on image data, and is provided in the image forming unit, and heat-fixes the image formed on the sheet A fixing unit; and a control unit that controls a lifting operation of the lifting unit and a control unit that controls sheet feeding from the sheet feeding tray, the control unit being the uppermost sheet feeding tray of the sheet feeding trays When the other is used, the lifting unit provided in the uppermost tray is lowered and the lifting unit provided in the other feeding tray is raised for feeding. When the above paper tray is used as the paper feed tray Since the elevating unit provided in the uppermost sheet feeding tray is raised for paper feeding, in principle, the elevating unit in the uppermost sheet feeding tray is lowered to form a space between the fixing unit and the like as a heat source. In addition, a space for heat to escape is ensured, and temperature rise in the machine can be effectively prevented. As a result, it is possible to avoid the occurrence of defects without being affected by the ambient temperature and the continuous operation time.

Below, one Embodiment of this invention is described based on FIGS. 1-4.
FIG. 1 schematically shows an image forming apparatus 1 according to the present invention.
In FIG. 1, 10 is an image forming unit, 20 is a sheet feeding unit including a plurality of sheet feeding trays, and 30 is a transport unit.

In the image forming apparatus 1, an image such as a document is read by a document reading unit (not shown) and temporarily recorded in an image memory of the storage unit 3 shown in FIG. 2.
The image forming unit 10 is provided with a charger, an image exposure unit, and a developing unit around the periphery of the photoconductor 11 that rotates. The surface of the photoconductor 11 charged by the charger is recorded in the storage unit 3. The image exposure of the image exposure unit is performed based on the image information of the original, and a latent image is formed on the surface of the photoreceptor 11. The latent image is developed by a developing device to become a toner image.

In the image forming apparatus 1, a plurality of paper feed trays 21, 22, and 23 that respectively store sheets are arranged in the upper and lower stages (three stages in the figure) below the image forming unit 10. These paper feed trays 21, 22, and 23 are the main components of the paper feed unit 20.
The paper feed trays 21 to 23 have elevating units 210, 220, and 230 that can be moved up and down by stacking sheets, and these elevating units 210, 220, and 230 are moved up and down by a driving device (not shown). It is configured.

In the state where the power source of the image forming apparatus 1 is turned on, each of the elevating units 210, 220, and 230 has conventionally been loaded with sheets from a feed roller (not shown) as shown in FIG. In order to be able to feed paper immediately, the upper surface of the paper is raised so as to be at the upper end position (directly below the paper feed roller) in all the paper feed trays, and the upper surface of the paper is detected by an upper surface detection sensor (not shown). However, in the image forming apparatus of the present invention, as a general rule, the elevating unit 210 provided in the uppermost paper feed tray 21 is lowered to the lower limit position as shown in FIG. In the paper feed trays 22 and 23, the elevating units 220 and 230 are raised in preparation for paper feed so that the paper can be fed efficiently.
Each of the paper feed trays 21, 22, and 23 is provided with a paper feed fan 211 (only the paper feed fan 211 of the paper feed tray 21 is illustrated) in order to assist the paper supply during paper supply.

  As described above, the image forming apparatus 1 includes the transport unit 30 that transports the paper fed from the paper feed trays 21 to 23 to the image forming unit 10 and transports the paper after the image formation to the paper discharge destination. ing. The transport unit 30 includes a transport path 31 and a transport roller. The transport path 31 includes a reverse transport path 32 for performing double-sided printing on a sheet by inverting the sheet. The reverse conveyance path 32 is positioned on the downstream side of the fixing unit 12, on the lower side of the image forming apparatus 10, and on the upper side of the paper feed tray 21, and joins the conveyance path 31 on the upstream side of the image forming unit 10. ing.

The toner image on the photoreceptor 11 is transferred by the image forming unit 10 to the sheet conveyed through the conveyance path 31. The sheet holding the toner image is fixed by being pressed and heated by a fixing unit 12 provided in the image forming unit 10. When single-sided printing is selected, the sheet that has been fixed and has been printed on the front surface travels straight through the conveyance path 31 and is discharged outside the apparatus.
On the other hand, when double-sided printing is selected, the paper having the printed image on the front surface after fixing is conveyed to the reverse reverse conveyance path 32. The conveyed sheet is reversed by the reverse conveyance path 32 and conveyed to the upstream side of the image forming unit 10 by the conveyance roller. The paper holding the toner image on the back side is transferred by the photoconductor 11 and fixed by the fixing unit 12 in the same manner as described above, and is discharged outside the apparatus.

Next, FIG. 2 is a control block diagram of the image forming apparatus 1.
The image forming apparatus 1 includes a control unit 2 that controls the entire image forming apparatus. The control unit 2 mainly includes a CPU and a program that operates the CPU. The control unit 2 is connected to a storage unit 3 having an image memory and a nonvolatile memory.
The nonvolatile memory of the storage unit 3 stores image data acquired by reading a document, setting data of the image forming apparatus 1, process control parameters, and the like, and is read and written by the control unit 2 as necessary. In addition, the storage unit 3 stores readable data (timing data) serving as a reference when controlling the lifting / lowering operation of the lifting / lowering unit 210 in the paper feed tray 21. These data may be set as initial values, or may be set and input by an operator through an operation unit (not shown) as necessary. The sheet number data includes the sheet number data (rising timing data) for raising the elevating unit 210 when the sheet feeding tray 21 is used for image formation within the predetermined number of sheets, and the sheet feeding tray 21 within the predetermined number of sheets. The number of pieces of data (lowering timing data) for lowering the lifting / lowering unit 210 when not used in image formation is included, but in these data, both may be set to the same number or different. The number of sheets may be set.

Further, the control unit 2 is connected to the control unit 2 in a controllable manner including the paper supply trays 21... 23, and is provided with elevating units 210, 220, 230, and a fan 211 (only those provided in the paper supply tray 21. Can be controlled by the control unit 2.
Further, the control unit 2 transports the paper fed from the paper feed trays 21 to 23 to the transfer position of the image forming unit 10 through the transport path 31, and then transports the paper from the fixing position to the outside of the apparatus. A conveyance unit 30 that conveys the sheet from the fixing position to the image forming unit 10 and the paper discharge destination via the reverse conveyance path 32 and the conveyance path 31 is connected to be controllable.

Below, the control procedure of the raising / lowering part in this embodiment is demonstrated based on the flowchart of FIG.
First, image data is acquired, and a job is submitted when the operator presses a print start button on the operation unit. The control unit 2 manages one or a plurality of jobs. Therefore, the tray information used in these jobs is acquired for each page, and the contents of all jobs are confirmed (step s1). If there is an interrupt process or the like during the execution of the job, the tray information in the page order is changed, so the contents of all jobs are checked again.

The control unit 2 lowers the elevating unit 210 to the lower limit position as an initial value by turning on the power before starting the job, and elevates the elevating units 220 and 230 in preparation for paper feeding.
The control unit 2 starts a job and acquires predetermined number of pieces of data for raising / lowering control of the elevating unit 210 from the storage unit 3 as ascending and descending timing data (step s2). Based on the data, the control unit 2 determines whether or not to use the tray 21 within a predetermined number of pages for each page from the start of the job. An instruction to raise the elevating unit 210 of 21 is prepared, and an instruction to lower the elevating unit 210 of the paper feed tray 21 is prepared for a page that does not use the tray 21 within a predetermined number of sheets. The command is prepared as a table corresponding to the page. It should be noted that the predetermined number at the time of the rise determination and the predetermined number at the time of the decrease determination are the same number or different numbers.

  With the start of the job, the control unit 2 determines whether or not the raising / lowering unit 210 needs to be raised within the predetermined number of sheets from the start, that is, whether it is at the rising timing (step s3). When it is not the ascending timing (NO in step s3), the elevating unit 210 is kept lowered and the rotation of the blower fan 211 for cooling is controlled (step s4), and the process proceeds to step s6. The whirling fan is normally controlled for rotation according to the paper feeding method and the type of paper. However, when the whirling fan is used for cooling, it is desirable to rotate at the maximum rotational speed, for example, in consideration of cooling efficiency.

  On the other hand, if the uppermost sheet feeding tray is scheduled to be used within the predetermined number of sheets at the start and the rising timing is reached (step s3, YES), the control unit 2 raises the uppermost sheet feeding tray 21 (step s5). . In this way, by raising the elevating unit 210 of the uppermost sheet feeding tray 21 in advance, the waiting time is shortened and the sheet feeding in the uppermost sheet feeding tray is shortened without waiting for the time required for raising and lowering. Is possible. Therefore, the predetermined number used for the determination of the rise of the tray 1 is determined in consideration of the time required for the elevating unit 210 to rise. If the number data is too large, the time during which the elevating unit 210 is raised becomes long, and the temperature inside the apparatus tends to rise. On the other hand, if the number data is too small, the elevating unit 210 does not rise in time when the tray 1 is used, so that standby is required and processing efficiency decreases. For this reason, it is desirable to set the number of sheets so that the elevating unit finishes rising before use so that paper can be fed immediately when the uppermost tray is used.

  Following the execution of step s4 or s5, copying is started (step s6). Along with the start of copying, the procedure is executed while counting the number of sheets (step s7). For each number of sheets, it is determined whether or not the elevating unit 210 of the uppermost sheet feed tray 21 is in the lower position or descending (step s8). If the elevating unit 210 is in the lower position or descending (step s8, YES), the control unit 2 determines whether or not to use the uppermost sheet feed tray 21 within the predetermined number of sheets, that is, whether or not it is in the rising timing (step s9). When it is the rising timing, the control unit 2 stops the rotation (for cooling) of the separation fan 211 provided in the uppermost sheet feeding tray 21 and raises the lifting unit 210 in preparation for sheet feeding (step s10). Until the process is completed, the process returns to step 7 for each number of sheets and the same procedure is repeated (step s11). On the other hand, if it is not in the ascending timing in step s9, the same procedure is repeated by returning to step 7 for each number of sheets until the job is completed without performing the elevation control of the elevation unit 210 (step s11).

Further, in step s8, when the lifting / lowering unit 210 is not in the lower position or descending (step s8, NO), that is, when the lifting / lowering unit 210 is in the rising position or rising, the control unit 2 determines the predetermined number (20 It is determined whether or not the uppermost paper feed tray 21 is not used within the (sheet), that is, whether or not it is the lowering timing (step s12). When it is the lowering timing, the control unit 2 lowers the elevating unit 210 and controls the rotation of the fan 211 provided in the uppermost sheet feeding tray 21 for cooling (step s13). Every time the process returns to step 7, the same procedure is repeated (step s11). If it is not the lowering timing, the same procedure is repeated by returning to step 7 for each number of sheets until the job is completed without lowering the elevating unit 210 (step s11).
After the job is finished, in accordance with the principle, the elevating unit 210 in the uppermost sheet feed tray 21 is lowered to the lower limit position, and the fan 211 is further rotated for cooling (step s14).

  Next, FIG. 4 shows an example in which the raising / lowering control of the raising / lowering unit provided in the uppermost tray is performed by the above procedure. In FIG. 4, the trays used in the page order are grasped by checking the contents of the job. In the following description, the paper feed tray 21 will be described as tray 1, the paper feed tray 22 will be described as tray 2, and the paper feed tray 23 will be described as tray 3. Further, in this example, the same number of 20 sheets is set as the predetermined number of times for rising or lowering.

In the example of FIG. 4, since the tray 1 is used within 20 sheets (third sheet) at the start of the job, the elevating unit 210 of the tray 1 is raised up to the third sheet print when the job starts. For the third sheet, printing is performed on the rising tray 1.
In the fourth sheet, the raising / lowering part 210 of the tray 1 is in the ascending position, and the tray 1 is not used within 20 sheets (up to the 23rd sheet). The burning fan 211 is rotated for cooling.
In the fifth to seventh sheets, the elevating unit 210 of the tray 1 is in the lower position, but the tray 1 is not used within 20 sheets, so the elevating unit 210 is kept lowered without being raised.
In the eighth sheet, the tray 1 is in the lowered position, and the tray 1 is used within 20 sheets (the 27th sheet). Therefore, it is the rising timing, and the firing fan 211 is stopped and the elevating unit 210 of the tray 1 is raised. .
From the 9th sheet to the 26th sheet, the elevating part 210 of the tray 1 is kept raised in preparation for the 27th sheet. On the 27th and 28th sheets, printing is performed using the tray 1 in the raised position.

In the 29th sheet, the tray 1 is in the raised position, and since the tray 1 is used within 20 sheets (36th sheet), the tray 1 is kept raised up to the 36th sheet, not at the lowering timing. On the 36th sheet, printing is performed using the tray 1 in the raised position.
In the 37th sheet, the sheet feed tray 1 is raised, and the tray 1 is not used within 20 sheets. Therefore, at the lowering timing, the raising / lowering part 210 of the tray 1 is lowered and the fan 211 is rotated for cooling. .

In the 38th to 40th sheets, since the tray 1 is not used within 20 sheets, the elevating part 210 of the tray 1 is kept lowered without being raised.
In the 41st sheet, since the tray 1 is used within 20 sheets (60th sheet), it is an ascending timing, the firing fan 211 is stopped, and the lifting / lowering unit 210 of the tray 1 is installed in preparation for the 60th sheet printing. Keep it up. The elevating part 210 of the tray 1 is kept raised up to the 60th sheet. The raising / lowering of the raising / lowering part 210 in the paper feed tray 1 is controlled until the end of the job by the above procedure. After the job is completed, the paper feed unit 210 of the tray 1 is lowered, and the fan 211 is rotated for cooling.

  As in the above example, the elevating unit 210 can obtain a time for the tray 1 to descend to the lower limit position even if the tray 1 is frequently used, and prevents the in-machine temperature from rising by securing a space above. In addition, when the tray 1 is scheduled to be used, the lifting unit is raised in advance at a timing in time for feeding from the tray 1, so that the job can be efficiently executed without waiting for the lifting unit to rise for a long time. it can.

Next, the raising / lowering control of the raising / lowering part 210 at the time of automatic paper-feed tray selection being performed is demonstrated based on FIG.
Note that automatic paper feed tray selection is a function that automatically selects paper feed trays that match the paper size and paper type when paper runs out in the paper feed tray that is feeding paper and continues feeding. Yes, executed by the control unit 2. Out of paper can be recognized by the control unit 2 based on the detection result of a zero sheet detection sensor (such as a light reflection sensor) provided in each paper feed tray.

  When a job other than tray 1 is designated as the used paper feed tray and the job is executed, if there is paper in the designated paper feed tray (step sa1, NO), automatic tray selection is not performed. In this case, the tray 1 is not selected (step sa3), and the lowering of the tray 1 is confirmed (step sa8). If the tray 1 is not lowered, the tray 1 is lowered (step sa9), and printing is performed on the designated tray until printing is completed (steps sa6 and sa7).

  On the other hand, when the designated tray runs out of paper (YES at step sa1), a paper feed tray having the same paper size and paper type is automatically selected (designated) by automatic tray selection (step sa2). When selecting a tray, for example, the control unit 2 checks and selects trays that meet the conditions sequentially from the top, or sets a priority of trays in advance and checks and selects the tray according to the priority. To go. The priority order is stored in the storage unit 3.

  It is determined whether or not the tray 1 is selected by the automatic tray selection (step sa3). If the tray 1 is not selected, it is determined whether or not the elevating unit 210 of the tray 1 is in the lower position (step sa8). If not, the elevating unit 210 of the tray 1 is moved to the lower position (step sa8, NO). The fan is lowered and the fan 211 is rotated for cooling (step sa9). If the elevating unit 210 of the tray 1 is in the lower position (step sa8, YES), the lower position of the elevating unit 210 is maintained as it is. After that, printing is continued until the job is finished on the tray designated by the automatic tray selection (steps sa6 and sa7).

  When the tray 1 is selected by the automatic tray selection (step sa3, YES), it is determined whether the elevating unit 210 of the tray 1 is in the lower position or descending (step sa4). If the raising / lowering part 210 of the tray 1 is not in the lower position or descending (step sa4, NO), printing is executed on the tray 1 (step sa6). On the other hand, if the raising / lowering unit 210 of the tray 1 is in the lower position or descending (step sa4, YES), the raising / lowering unit 210 of the tray 1 is raised in accordance with the paper feeding in the tray 1 (step sa5), and printing is executed. (Step sa6).

If the selection of the tray 1 is canceled during the job execution, for example, by supplying paper to the tray that is out of paper (step sa3, NO), if the elevating unit 210 of the tray 1 is in the raised position (step sa8, NO), the elevating part 210 of the tray 1 is lowered (step sa9), and a space is secured between the fixing part and the like.
In addition to the case where the selection of the tray 1 is canceled, in addition to the case where the paper size is changed and switched to another tray in the next job, or the paper in the uppermost tray 1 is exhausted during printing. There is a case of switching to another tray (same paper size).

Further, even after the job is completed, if the elevating unit 210 of the tray 1 is raised, the elevating unit 210 is lowered to the lower limit position (step sa10).
As described above, according to the present invention, even when automatic paper feed tray selection is executed, the uppermost paper feed tray can secure a space between the fixing unit and the like as much as possible to prevent the temperature inside the apparatus from rising. .

  As mentioned above, although this invention was demonstrated based on the said embodiment, this invention is not limited to the content of the said embodiment, A suitable change is possible unless it deviates from the scope of the present invention.

1 is a schematic diagram illustrating a mechanical configuration of an image forming apparatus according to an embodiment of the present invention. Similarly, it is a functional block diagram. Similarly, it is a flowchart which shows the raising / lowering control procedure of the raising / lowering part of an uppermost tray. Similarly, it is a flowchart which shows the specific example of the said raising / lowering control procedure. Similarly, it is a flowchart which shows the raising / lowering control procedure at the time of automatic tray selection.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Control part 3 Memory | storage part 10 Image forming part 11 Photoconductor 12 Fixing part 20 Paper feed part 21 Paper feed tray 210 Lifting part 211 Rolling fan 22 Paper feed tray 220 Lifting part 23 Paper feed tray 230 Lifting part

Claims (5)

  A plurality of upper and lower stages, a paper feed tray that stores paper in each of the paper feed trays, a lifting unit that is provided in the paper feed tray and moves up and down, and above the paper feed tray An image forming unit located on the side for forming an image on a sheet based on image data, a fixing unit provided in the image forming unit for heating and fixing an image formed on the sheet, and an ascending / descending operation of the elevating unit And a control unit that controls the sheet feeding from the sheet feeding tray, and when the control unit is a sheet feeding tray other than the uppermost sheet feeding tray, While raising and lowering parts provided in the uppermost sheet feeding tray are lowered, raising and lowering parts provided in the other sheet feeding trays are raised for feeding, and the uppermost sheet feeding tray is used as the used sheet feeding tray. To prepare for the uppermost paper feed tray Image forming apparatus characterized by raising provided with a lifting unit in the paper feed.   Each of the sheet feed trays is provided with a separation fan, and when the uppermost sheet supply tray is lowered, the control unit controls rotation of the sheet separation fan included in the sheet supply tray for cooling. The image forming apparatus according to claim 1.   The control unit has an automatic paper feed tray selection function. When the uppermost paper feed tray is selected by automatic paper feed tray selection, the elevating unit provided in the uppermost paper feed tray is lowered. 3. The image forming apparatus according to claim 1, wherein when the selection is canceled, the lifting / lowering unit is lowered when the lifting / lowering unit is raised in preparation for paper feeding.   The control unit has a function of managing one or a plurality of jobs, and uses the uppermost sheet feed tray within a predetermined number of sheets when executing one or a plurality of jobs or during the job execution. 4. The image forming apparatus according to claim 1, wherein when image formation is performed, the elevating unit of the paper feed tray is raised or raised in advance in preparation for paper feed. 5.   The control unit has a function of managing one or a plurality of jobs, and uses the uppermost sheet feed tray within a predetermined number of sheets when executing one or a plurality of jobs or during the job execution. 5. The image forming apparatus according to claim 1, wherein, when image formation is not performed, the elevating unit provided in the uppermost sheet feeding tray is lowered or the elevating unit in the raised position is lowered. The image forming apparatus described.

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