JP2013054235A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that reduces temperature of sheets after fixing to prevent welding of the stacked sheets by blocking.SOLUTION: A control unit controls an image forming apparatus 1 to print image data on one sheet. The control unit then controls an inserter 2 to stack a peelable tab sheet on the sheet after the printing. The control unit then determines whether or not the current number of printed sheets has reached a desired number of printed sheets to determine whether or not the printing has ended. If the printing has not ended, the control unit repeats the above processing.

Description

  The present invention relates to an image forming apparatus capable of lowering the temperature of a sheet after fixing.

  In an image forming apparatus having an electrophotographic thermal fixing device, an image is formed on a sheet by melting toner in the thermal fixing device. In general, sheets discharged from the image forming apparatus are stacked on a discharge apparatus such as a large-capacity stacker or a finisher. The paper stacked on the paper discharge device is called so-called blocking, in which toner is welded by the heat stored in the paper or the weight when the paper is bundled, and the stacked papers are bonded together. The phenomenon occurs. When blocking occurs, the toner image peels off on the image surface of the finished paper, and as a result, the printing result is impaired.

In an image forming apparatus, in order to deal with a larger number of printing papers and to deal with a wide variety of papers, the temperature for fixing an image is generally higher than that of ordinary printing papers. The amount of heat of the stacked sheet stack at the time is in an increasing direction.
Also, the number of sheets stacked on the paper discharge device is increasing due to the increase in capacity of a stacker or the like.
In general, as a countermeasure against this blocking, there is already known a method of lowering the temperature of a sheet after fixing by bringing the sheet into contact with a sheet conveyance path cooled by a cooling fan.

  In Patent Document 1, for the purpose of preventing blocking, an electrostatic latent image formed on an image carrier is developed with toner to form an image on a sheet material, and an image is formed by the image forming unit. A sheet material stacking unit for stacking the formed sheet material, and a blowing unit for exhausting air inside the apparatus to the outside of the apparatus and cooling the sheet material by sending air to the sheet material stacked on the sheet material stacking unit In the image forming apparatus having the above, a configuration using a control unit that controls the blowing condition of the blowing unit according to the state of the sheet material stacked on the sheet material stacking unit is disclosed.

However, the conventional countermeasure method requires a device for reducing the temperature of the paper after fixing by using a cooling fan, which causes a problem of increasing the size of the device and increasing the cost.
Therefore, there is an urgent need to provide an apparatus that can reduce the temperature of a sheet after fixing and prevent welding due to blocking of stacked sheets without using a cooling fan.
SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of lowering the temperature of a sheet after fixing and preventing welding due to blocking of stacked sheets. is there.

  According to the first aspect of the present invention, there is provided a detachable tab sheet made of a release sheet having a tab and having both sides infiltrated with silicon, and the tab sheet is stacked on the sheet after the image is printed. An inserter device that can be inserted, and a control unit that controls the inserter device so that one tab sheet is sandwiched before the next printed sheet is stacked on the printed sheet. It is characterized by.

  According to the present invention, it is possible to prevent welding due to blocking of stacked sheets by sandwiching one tab sheet having peelability between sheets after printing.

It is sectional drawing for demonstrating the printing apparatus which concerns on 1st Embodiment of this invention. FIG. 5 is a flowchart for controlling so that one sheet of peelable tab paper is sandwiched between one sheet after fixing in the printing apparatus according to the first embodiment of the present invention. FIG. FIG. 6 is a block diagram for explaining a control system of an image forming apparatus according to a second embodiment of the present invention. 6 is a flowchart for controlling a control unit so that a tabbed sheet having a peelable property is sandwiched between sheets according to a toner density of a printed matter in an image forming apparatus according to a second embodiment of the present invention. It is a perspective view for demonstrating the peelable tab paper used in 1st and 2nd embodiment. In 1st and 2nd embodiment, it is sectional drawing of the image forming apparatus for demonstrating the process of removing the tab paper 41 with peelability in the post process after printing.

An image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings.
In the present invention, in order to prevent the phenomenon of toner welding (blocking) caused by the heat of the paper discharged from the image forming apparatus and loaded on the paper discharge apparatus or the weight of the paper bundle itself, It is characterized in that the stacked sheets are prevented from being welded by sandwiching a peelable tab sheet at the time of stacking on a stacker or the like.

<First Embodiment>
FIG. 1 is a cross-sectional view for explaining a printing apparatus according to a first embodiment of the present invention.
The printing apparatus includes an image forming apparatus 1, an inserter 2 for inserting a tab sheet before the next printed sheet is stacked on the printed sheet, and a sheet discharge for discharging the fixed sheet. The apparatus 3 is provided.
The tab paper is a peelable paper made of a release paper having tabs and infiltrated with silicon on both sides. The inserter 2 can insert the tab data on the paper after printing the image data, and pinches the tab paper when the fixed paper is stacked on a large-capacity stacker or the like.

FIG. 2 is a flowchart for controlling so that one sheet of peelable tab paper is sandwiched between one sheet after fixing in the printing apparatus according to the first embodiment of the present invention. The image forming apparatus 1 includes a control unit (not shown). The control unit includes a ROM, a RAM, and a CPU. The CPU reads out a control program stored in the ROM and loads the image forming apparatus 1. Control.
First, in step S5, the control unit controls the image forming apparatus 1 to print image data on one sheet.

Next, in step S10, the control unit controls the inserter 2 so that a tab sheet having peelability is stacked on the printed sheet. As a result, one tab sheet can be inserted before the next printed sheet is stacked on the printed sheet.
Next, in step S15, the control unit determines whether or not printing is finished by determining whether or not the current number of printed sheets has reached a desired number of printed sheets. If printing has not been completed, the process returns to step S5 and the above processing is repeated.

Accordingly, the inserter 2 is controlled so that one tab sheet is sandwiched before the next printed sheet is stacked on the printed sheet. One tab sheet can be sandwiched between the two. As a result, it is possible to prevent the stacked sheets from being welded.
Note that the control unit may control the inserter 2 so that one tab sheet is stacked when the number of printed sheets reaches the reference number m. Further, the control unit may control the inserter 2 so as to variably set the reference number m. As a result, it is possible to sandwich tab sheets with peelability at an arbitrary number of printed sheets.

  Accordingly, it is possible to prevent the stacked sheets from being welded by sandwiching the peelable tab sheet when the fixed sheets are stacked on a large-capacity stacker or the like.

Second Embodiment
FIG. 3 is a block diagram for explaining a control system of the image forming apparatus according to the second embodiment of the present invention.
The image forming apparatus 21 includes an image forming apparatus control unit 22, a toner density detection unit 24 that detects toner density from image data, and an inserter control unit 23 that controls the inserter device 25.

FIG. 4 is a flowchart for controlling the image forming apparatus according to the second embodiment of the present invention so that a tabbed sheet having a peelable property is sandwiched between sheets, as judged from the toner density of the printed matter. It is. 3 includes a ROM, a RAM, and a CPU, and the CPU reads a control program stored in the ROM and controls the image forming apparatus 21 and the inserter control unit 23.
First, in step S30, the image forming apparatus control unit 22 controls the image forming apparatus to print image data on one sheet.

Next, in step S35, the image forming apparatus control unit 22 acquires the toner density of the print image from the toner density detection unit 24, and determines whether or not the toner density of the acquired print image exceeds a certain value.
Here, in step S40, when the toner density of the print image exceeds a certain value, the inserter control unit 23 is controlled so that one tab sheet having peelability is stacked from the inserter device 25. As a result, one tab sheet can be inserted before the next printed sheet is stacked on the printed sheet.
On the other hand, if it is determined in step S35 that the toner density of the print image does not exceed a certain value, the process proceeds to step S45.

Next, in step S45, the image forming apparatus control unit 22 determines whether or not printing is finished by determining whether or not the current number of printed sheets has reached a desired number of printed sheets. If printing has not been completed, the process returns to step S30 and the above processing is repeated.
Thus, for example, when printing image data consisting of a plurality of pages on a sheet, if the toner density of the print image exceeds a certain value, one sheet of tab paper with peelability is stacked from the inserter device 25. The tab sheet can be sandwiched only on a printing sheet having a toner density higher than a certain value and requiring heat dissipation.

Note that the image forming apparatus control unit 22 may control the inserter control unit 23 so that one tab sheet is stacked when the number of printed sheets reaches the reference number m. As a result, one tab sheet can be inserted before the next printed sheet m + 1 is stacked on the printed sheet m.
Further, the image forming apparatus control unit 22 may control the inserter control unit 23 so as to variably set the reference number m. As a result, it is possible to sandwich tab sheets with peelability at an arbitrary number of printed sheets.
Further, the image forming apparatus control unit 22 may control the inserter control unit 23 so that the reference number m is variably set according to the toner density of the print image acquired from the toner density detection unit 24. As a result, the reference number m can be reduced as the toner density increases.

  The tab sheet has a plurality of different sizes, and the image forming apparatus control unit 22 selects the tab sheet size in accordance with the size of the sheet at the time of printing, and instructs the inserter control unit 23 to The tab paper having a size matching the paper size at the time of printing can be used to cool the paper after printing.

FIG. 5 is a perspective view for explaining a releasable tab sheet used in the first and second embodiments.
The releasable tab paper 41 has one or more heat-dissipation cut portions 42 for radiating heat from a paper used for printing in a heat radiation direction (arrow) 43.
Here, the peelable tab paper 41 will be described.
Only the tab 41a protrudes from the paper used for printing so that the tab paper 41 with peelability can be easily removed by an operator's manual operation. When using a machine or the like for removing the tab paper 41 having peelability in a post-process after printing, it is not necessary to form a protruding shape like the tab 41a.

If the interval between the cut portions 42 is sufficiently wide, blocking may occur. Therefore, in practice, the interval between the cut portions 42 needs to be narrowed. Further, by sandwiching several sheets of paper with the cut portions 42, the toner on the fixed sheets is prevented from welding.
The peelable paper 41 is not necessary when a base material layer made of a base material such as paper and a sealing agent for sealing (such as PVA or polyethylene is used for glassine paper as the base material). And a release layer (silicone release agent), and a release layer (silicone release agent) 3 layers (two layers) are laminated, and in this embodiment, both sides are constituted by release layers, Even when papers with images fixed on both sides come into contact, the papers do not weld together.

  In the conventional blocking measure, in order to prevent toner welding, metal or the like is brought into contact with the paper, and the temperature of the paper is actively lowered by air cooling or water cooling. In this case, as described above, the toner is prevented from being welded by being sandwiched between a sheet on which an image is fixed with a sheet having releasability.

FIG. 6 is a cross-sectional view of the image forming apparatus for explaining a step of removing the peelable tab paper 41 in a post-printing step in the first and second embodiments. In order to remove the release paper sandwiched between the fixed papers, the apparatus shown in FIG. 6 is used.
Using the inserter 52, the print output sandwiching the release paper is once stacked on the stack device 60 as an output result.

Below the stacking device 60, rollers 58 and 59 for feeding paper are rotatably attached, and the sufficiently cooled paper is sent again. Behind this, there are two transport paths 56 and 57 for sorting paper, and according to the order of the paper stored in the image forming apparatus 51, it is possible to sort the print result and the release paper sent out by the inserter 52. It has become. The sheets sorted by the sorting device 53 can be discharged to separate discharge trays 54 and 55, respectively.
The sheets are stacked on the stacking device 60 to sufficiently cool the sheets. When sufficient cooling of the sheet is completed, the sheet is sent again from the apparatus to the subsequent post-processing apparatus.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Inserter 3 Paper discharge apparatus 21 Image forming apparatus 22 Image forming apparatus control part 23 Inserter control part 24 Toner density detection part 25 Inserter apparatus 41 Tab paper 41a Tab 42 Cutting part 43 Heat dissipation direction 51 Image forming apparatus 52 Inserter 53 Sorting device 54, 55 Discharge tray 56, 57 Transport path 58, 59 Roller 60 Stack device

JP 2001-242769 A

Claims (6)

Removable tab paper made of release paper with tabs and silicon infiltrated on both sides;
An inserter device that can be inserted in such a manner that the tab sheets are stacked on a sheet after printing an image;
Control means for controlling the inserter device so as to sandwich one tab sheet before the next printed sheet is stacked on the printed sheet;
An image forming apparatus comprising:   The image forming apparatus according to claim 1, wherein the control unit controls the inserter device to sandwich one tab sheet when the number of sheets after printing reaches a reference number.   The image forming apparatus according to claim 2, wherein the control unit controls the reference number to be arbitrarily set. Detecting means for detecting the toner density of the image printed on the paper;
2. The control unit according to claim 1, wherein when the toner density of the image acquired by the detection unit exceeds a predetermined value, the control unit controls the inserter device to stack one tab sheet. Image forming apparatus.   The image forming apparatus according to claim 1, wherein a cut portion for cooling the printed paper is provided in the tab paper. The tab paper has a plurality of different sizes,
The image forming apparatus according to claim 1, wherein the control unit selects the size of the tab sheet according to the size of the sheet at the time of printing and instructs the inserter apparatus.

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