JPH04248582A - Image forming device - Google Patents

Abstract

PURPOSE:To offer an image forming device capable of automatically cleaning the soil of toner on the heat roller of a fixing part and to prevent the degradation of printing quality and the jamming of a form, on the image forming device which can judge the soiling of the toner on the heat roller of the fixing part and sent out the sheet without printing. CONSTITUTION:In the image forming device, an electrostatic latent image formed on an image forming body 51 is developed with the toner, the toner image of the image forming body 51 is transferred to a recording medium 20 sent out from a medium supplying part 2, and then, a transfer image is fixed by the heat roller 58 on the fixing part 57 having the heat roller 58. Further, a constitution is adopted so that a judging means 8 judging whether the heat roller 58 is used or not till the soil with the toner of the heat roller 58 reaches a prescribed level, is provided, and the unprinting/sending out of the recording medium 20 is commanded, when the heat roller 58 is used till the soil reaches the prescribed level.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to an image forming apparatus such as an electrophotographic printing apparatus, and in particular, it is possible to determine whether toner stains on a heat roller of a fixing section are present using a determining means and to feed out paper without printing. The present invention relates to an image forming apparatus.

[0002] In recent years, with the development of office automation, there has been an increasing demand for character image information output devices that can use plain paper, have low noise, and produce beautiful prints.

[0003] For this reason, copying machines using electrophotographic technology,
Facsimile machines, printers, etc. are provided. In these devices, the printing paper with the toner image transferred passes between a heat roller and a pressure roller and is thermally fixed, so the toner adheres to the heat roller and becomes dirty, so it is cleaned with a felt cleaner. Felt cleaners also become dirty and need to be replaced, which is troublesome and time consuming, and failure to replace them can lead to deterioration in print quality and occurrence of paper jams, so a method that can be easily cleaned is desired.

0004

2. Description of the Related Art FIG. 8 shows an internal side view of an electrophotographic printing apparatus. In the figure, 1 is the cassette mounting part, 2
3 is a cassette, 3 is a feed roller, 4 is a conveyance path, 5 is a printer section, and 6 is a stacker.

The printer section 5 includes an optical unit 50, a photosensitive drum 51a, a cleaner 52, a charging section 53, a developing section 54, a transfer section 55, a static eliminating section 56, and a fixing section 57a. A cassette 2a is set in the cassette mounting section 1, and a desired size of printing paper (
20a (hereinafter referred to as paper) are stored in an accumulated manner.

With this configuration, when the power of the apparatus is turned on, the heat roller 58a of the fixing section 57a is heated to a predetermined temperature and becomes ready for printing, and the paper 20a is moved from the cassette 2a in the direction of arrow A based on the print instruction signal. Take out the
It is conveyed along the conveyance path 4 and sent below the photosensitive drum 51a. By this time, the photosensitive drum 51a has been neutralized by the static eliminating section 56, residual toner has been cleaned by the cleaner 52, and charged again by the charging section 53.

Therefore, optical data irradiated from an optical unit 50 composed of a laser light source or the like is transmitted to a photosensitive drum 51.
a, and the electrostatic image formed on the photosensitive drum 51a is developed into a toner image in the developing section 54, transferred to the paper 20a in the transfer section 55, and then transferred to the fixing section 57a by a heat roller 58a and a pressure roller. The paper 20a is held between the paper sheets 59 and heated and pressurized to fix the paper 20a, and then sent to the stacker 6.

[0008] The toner is a powder made of a resin material, carbon, dye, etc. solidified with wax, and is used as a developer by mixing it with a carrier coated with a magnetic material, mainly fine iron powder, with a resin material.

Here, the configuration of the fixing section 57a is shown in FIG.
To explain, as shown in the figure, the heat rollers 58a,
In addition to the pressure roller 59, a separation claw 60 and a cleaning wiper 61 are attached to the fixing section frame 62, respectively.

The heat roller 58a has a built-in heater lamp 63, the pressure roller 59 is pressed by a spring 64 and rolls into contact with the heat roller 58a, and the separation claw 60
The tip of the paper 20a comes into contact with the heat roller 58a and separates the paper 20a from the heat roller 58a.

The cleaning wiper 61 is made of felt impregnated with silicone oil or the like, for example.
The heat roller 5 contacts the rotating heat roller 58a.
Clean toner residue adhering to 8a.

0012

[Problems to be Solved by the Invention] According to the above conventional method, the toner image is fixed on the paper by passing the paper to which the toner has been transferred between the heat roller and the pressure roller. Some of the toner may adhere to the roller as residue and be transferred to subsequent sheets of paper, reducing print quality, or paper may not enter smoothly between the heat roller and pressure roller, resulting in paper jams. To prevent this, a cleaning wiper is used to clean the product. However, the cleaning wiper gets dirty, so we replace it regularly or at a timely basis by visually judging the print quality, but because it takes time and effort, we tend to neglect replacing the cleaning wiper, which can cause a decline in print quality and paper jams. There is a problem with inviting people.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that can automatically clean the toner stains on the heat roller of the fixing section to prevent deterioration in print quality and paper jam.

[0014]

[Means for Solving the Problems] FIG. 1 is a diagram showing the basic configuration of the present invention. In the figure, 2 is a medium supply unit, 20 is a recording medium, 51 is an image forming body, 57 is a fixing unit having a heat roller 58, and 8 is a fixing unit that has a heat roller 58 until the toner stain on the heat roller 58 reaches a predetermined level. This is a judgment means to judge whether or not it has been used.

Therefore, when the heat roller 58 is used in the fixing section 57 until the toner stain on the heat roller 58 reaches a predetermined level, a command is given to feed out the recording medium 20 without printing.

[0016]

[Operation] After the electrostatic image formed on the image forming body 51 is developed with toner and the toner image on the image forming body 51 is transferred onto the recording medium 20 fed out from the medium supply section 2, the fixing section 57 uses a heated roller. 58, the printing operation for fixing the transferred image is repeatedly performed, and when the determining means 8 determines that the thermal roller 58 has been used until the toner stain on the thermal roller 58 reaches a predetermined level, the recording medium 20 is fed out without printing. By commanding the recording medium 2 from the medium supply unit 2 while printing is stopped,
0 is fed out, and the unprinted recording medium 20 is sent to the fixing section 57, where the toner stains on the heat roller 58 adhere to the recording medium 20 and are cleaned.

[0017] In this way, the cleaning of the heat roller 58 is automatically performed in a timely manner, and it is possible to prevent deterioration in print quality and paper jams due to toner stains on the heat roller 58.

[0018]

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 2 to 4. The same reference numerals indicate the same objects throughout the figures.

FIG. 2 shows a configuration diagram of an embodiment in which the present invention is applied to the electrophotographic printing apparatus described in the conventional example. Figure 2
The photosensitive drum 51a and the heat roller 58a correspond to the image forming body 51 and the heat roller 58 in FIG. 1, respectively, and the cassette 2a and feeding roller 3 in FIG. Counter 8a and sheet number setting section 9 in FIG.
(The first counting means in claim 2) corresponds to the determining means 8 in FIG.

FIG. 2(a) is a side view of the fixing section 57b.
As shown in the figure, the cleaning wiper 61 is removed from the fixing section 57a described in the conventional example. Figure 2(b)
1 is a control block diagram for cleaning the heat roller 58a. In the figure, the control section 7 controls each section mentioned above, performs printing based on print data input from the outside, and collects a predetermined number of sheets N1 from the counter 8a. When receiving a count-out signal indicating that the paper 20a has been printed, a command is given to feed out the paper 20a without printing.

When the counter 8a counts the number of printed sheets N1 up to the number set in the number of sheets setting section 9, it issues a count-out signal. The number of sheets setting section 9 is a memory in which a predetermined number N1 of printed sheets is set in advance. Here, the predetermined number of printed sheets N1 is the cumulative number of printed sheets on which toner stains on the heat roller 58a of the fixing unit 57b are fixed, i.e.
Therefore, the cumulative number of printed sheets (for example, N1 = 2
00 sheets) is set.

Since it has such a configuration and function, the operation will be explained with reference to the flow charts and time charts of FIGS. 3 and 4. First, when the power of the device shown in FIG. 4(a) is turned on, the heat roller 58a is heated. Ru. During this time, the cassette 2a containing the paper 20a of the desired size is loaded into the cassette loading section 1. ■When the heat roller 58a reaches a temperature that allows fixing, printing starts as shown in FIGS. 4(b) and 4(c), and the counter 8a cumulatively counts the number of printed sheets each time printing is performed on the paper 20a. . ■Figure 4(c)
Then, the counter 8a indicates the number N1 set in the number setting section 9.
When the count is reached, a count-out signal is sent,
The control unit 7 instructs the paper 20a to be fed out without printing. 4. Then, as shown in FIGS. 4(b) and 4(d), the motor M is activated by the motor driver 70 while the printing operation is stopped.
1 is driven, the paper 20a is fed out by the feeding roller 3, and the paper 20a passes between the heat roller 58a and the pressure roller 59, and the toner residue attached to the heat roller 58a and the pressure roller 59 is removed. The toner stains transferred and attached to the paper 20a are cleaned. (2) The counter 8a is then cleared and counting starts again from the next printing.

In this way, when the total number of printed sheets reaches the predetermined number N1, the heat roller 58a and the pressure roller 59 can be automatically cleaned. Figure 5
A different example (1) is shown below. 5 is different from the embodiment shown in FIG. 2 in that instead of cleaning with a predetermined cumulative number of printed sheets N1, cleaning is performed with a predetermined cumulative number of printed pixels, so that characters, etc. printed on the paper 20a can be cleaned. Since the number of pixels of an image varies depending on the size of the printing rate, and the dirt on the heat roller 58a progresses in accordance with the number of pixels, the timing of cleaning becomes more accurate. The mechanism is similar to the previous embodiment. In FIG. 5, the same symbols as in FIG. 2(b) indicate the same objects.

The cassette 2a and feed roller 3 shown in FIG. 5 correspond to the medium supply section 2 shown in FIG. Further, the counter 8b and the pixel number setting section 9a in FIG.
This also corresponds to the second counting means of claim 3.

In the block diagram of FIG. 5, a control section 7a controls each of the above sections, performs printing based on print data input from the outside, and counts out a predetermined cumulative number of printed primes from a counter 8b. When the page being printed is completed when the signal is received, a command is given to feed out the paper 20a without printing.

The counter 8b issues a count-out signal when it cumulatively counts pixels up to the pixel number p1 set in the pixel number setting section 9a. The pixel number setting section 9a is a memory in which a predetermined number of pixels p1 is set in advance. Here, the predetermined number of pixels p1 is determined by the fact that toner stains on the heat roller 58a of the fixing unit 57b progress according to the cumulative number of pixels, that is, the number of fixed pixels, so the stains have progressed to a certain extent and there is no printing. Cumulative number of pixels corresponding to the level that can be cleaned by the paper 20a (for example, p1 = 10 million pixels)
is set.

With such a configuration and function, the counter 8 can count the number of pixels on the plurality of sheets of paper 20a that are sequentially printed.
When the predetermined pixel number p1 set in the pixel number setting section 9a is reached, the control section 7a instructs the next paper 20a to be delivered without printing when the page being printed is finished. As in the above embodiment, paper 2 is printed when the printing operation is stopped.
By feeding out the roller 0a, the heat roller 58a and the pressure roller 59 are cleaned.

In this way, when the cumulative number of printed pixels reaches the predetermined number p1, the heat roller 5 is automatically
8a and the pressure roller 59 can be cleaned. Further, FIG. 6 shows a different embodiment (2). FIG. 6 shows the embodiment explained in FIGS. 2 and 5 and a different embodiment (
The difference from 1) is that instead of counting the cumulative number of printed sheets or the cumulative number of prime pixels and cleaning when the predetermined number of sheets N1 or the predetermined number of pixels p1 is reached, the cumulative number of pixels is counted up to a predetermined number of sheets. By calculating the average number of pixels per sheet and cleaning at a predetermined cumulative number of sheets corresponding to that value, it is possible to more accurately time cleaning when continuing printing with little variation in print rate. can. The mechanism is similar to the previous embodiment. The same reference numerals as in FIGS. 2 and 5 indicate the same objects.

The cassette 2a and feed roller 3 in FIG. 6 correspond to the medium supply section 2 in FIG. 1, and the counter 8c in FIG.
8d, number setting sections 9b and 9c, calculation section 10, and cumulative number setting table 11 correspond to the determining means 8 in FIG. Further, the counter 8c, the counter 8d, the calculation unit 10, and the cumulative number setting table 11 in FIG.
This corresponds to the counting means, the fourth counting means, the calculation means, and the setting table, respectively.

In the block diagram of FIG. 6, a control section 7b controls each of the above sections and performs printing based on print data input from the outside, and a counter 8c controls a predetermined value set in advance in the number of sheets setting section 9b. When counting the number of sheets n, the counter 8d calculates the average number of pixels per sheet pm (=p/n) from the counted cumulative number of pixels p, and corresponds to the average number of pixels pm set in the cumulative number setting table 11. Read the cumulative number of printed sheets N and set the number of sheets to be set in the number setting section 9
c, and when the count of the counter 8c reaches the set cumulative number of printed sheets N, a command is given to feed out the paper 20a without printing.

The counter 8c cumulatively counts the number of printed sheets, and when it counts the number of printed sheets n (for example, 10 sheets) set in the number of sheets setting section 9b, it notifies the control section 7b and also sends the number of printed sheets n to the calculation section 10. The set cumulative number of printed sheets N set in the number of sheets setting section 9c is transmitted and continues counting.
The count-out signal is then sent.

The counter 8d cumulatively counts the number of pixels p until the counter 8c counts the number of printed sheets n, and
Send to. The calculation unit 10 calculates the average number of pixels per sheet of paper 20a based on the number of printed sheets n and the cumulative number of pixels p.
Calculate.

As shown in the figure, the cumulative number setting table 11 has a predetermined cumulative number N corresponding to each of a plurality of average pixel numbers pm.
is the memory set. Since it has such a configuration and function, the operation will be explained next with reference to the flowchart of FIG. ■First, when you turn on the power of the device, the heat roller 5
8a is heated, and during this time the cassette 2a is set in the apparatus, and when the heat roller 58a reaches a temperature that allows fixing, printing is started and the counters 8c and 8d start counting. (2) When the counter 8c cumulatively counts the number of printed sheets n set in the number setting section 9b, it notifies the control section 7b. (2) The counter 8d transmits the cumulatively counted number of printing pixels p to the calculation unit 10 according to a command from the control unit 7b. (2) The calculation unit 10 calculates the average number of pixels per sheet pm by dividing the cumulative number of pixels p by the cumulative number of printed sheets n. ■Control unit 7b
calculates the corresponding predetermined cumulative number N set in the cumulative number setting table 11 based on the average pixel number pm calculated by the calculation unit 10 (for example, if pm = 50,000 pixels, N
= 300 sheets) Set in the number of sheets setting section 9c. (2) Then, when the cumulative number of printed sheets on the counter 8c reaches a predetermined cumulative number N, the control section 7b instructs the paper 20a to be fed out without printing. (2) Then, while the printing operation is stopped, the paper 20a is fed out, and the paper 20a passes between the heat roller 58a and the pressure roller 59, and the paper 20a passes between the heat roller 58a and the pressure roller 59.
Then, the pressure roller 59 is cleaned of toner stains.

In this manner, the heat roller 58a and the pressure roller 59 can be automatically cleaned when the number of printed sheets N corresponding to the average number of pixels pm has been counted.

Therefore, according to the above embodiment and the different embodiments (1) and (2), when a predetermined cumulative number of sheets or a predetermined cumulative number of pixels is reached, the heat roller 58a of the fixing unit 57b is automatically fed out without printing. and pressure roller 5
9 can be cleaned, and the felt cleaner described in the conventional example can be omitted, which saves time and effort for replacement, further reduces space, and makes it possible to downsize the fixing section.

[0036]

As explained above, according to the present invention, a determination means is provided for determining whether or not the heat roller has been used until the toner dirt on the heat roller reaches a predetermined level. By issuing a command to feed the recording medium without printing when the heat roller has been used until the temperature is reached, the print quality is ensured by automatically cleaning the toner stains on the heat roller in the fixing section with the recording medium that has been fed out without printing. In addition, unlike the conventional example, there is no need to provide a felt cleaner, which saves time and effort for replacement.Furthermore, the fixing section can be made smaller, contributing to the miniaturization of the apparatus.

[Brief explanation of the drawing]

[Figure 1] Principle configuration diagram of the present invention

[Figure 2] Block diagram showing an embodiment of the present invention

[Figure 3]
Example flowchart

[Figure 4] Time chart of the example

[Figure 5] Block diagram showing different embodiment (1)

[
Figure 6: Block diagram showing different embodiment (2)

[Figure 7] Flowchart of different embodiment (2)

[Figure 8
] Internal side view of electrophotographic printing device

[Figure 9] Side view of a fixing unit showing a conventional example

[Explanation of symbols]

2 is a medium supply unit, 2a is a cassette, 3 is a feeding roller, 7, 7a, 7b are control units, 8 is a judgment means, 8a to 8d are counters, 9, 9b, 9c are sheet number setting units, 9a is a pixel number setting 10 is a calculation unit, 11 is a cumulative number setting table, 20 is a recording medium,
20a is paper, 51 is an image forming body, 51a is a photosensitive drum, 57, 57a, 57b are fixing units,

Claims (4)

[Claims] 1. The electrostatic image formed on the image forming body (51) is developed with toner, and the toner of the image forming body (51) is transferred onto the recording medium (20) fed out from the medium supply section (2). After transferring the image, a fixing section (57) having a heat roller (58)
), and whether or not the heat roller (58) is used until the toner stain on the heat roller (58) reaches a predetermined level. The image forming apparatus is characterized in that the image forming apparatus comprises a determining means (8) for determining the temperature, and instructs the recording medium (20) to be fed out without printing when the heat roller (58) is used until the predetermined level is reached. Device. 2. The image forming apparatus according to claim 1, wherein the determining means (8) is a first counting means that cumulatively counts the number of printed sheets up to a predetermined number. 3. The determining means (8) is a second counting means that cumulatively counts the number of pixels of the electrostatic image formed on the image forming body (51) up to a predetermined number. Item 1. Image forming device. 4. The determining means (8) comprises a third counting means for counting the number of printed sheets and a fourth counting means for cumulatively counting the number of pixels of the electrostatic image formed on the image forming body (51). and a calculating means for calculating the average number of pixels per sheet based on the cumulative number of sheets by the third counting means and the cumulative number of pixels by the fourth counting means when printing of a predetermined number of sheets is completed; and a setting table in which a predetermined cumulative number of sheets corresponding to the average number of pixels is set, and when the third counting means counts the predetermined cumulative number of sheets corresponding to the average number of pixels calculated by the calculation means, no printing is performed. 2. The image forming apparatus according to claim 1, further comprising a command to feed out the image forming apparatus.