JPH0887201A - Paper thickness detecting device and printer - Google Patents

Abstract

PURPOSE: To provide a paper thickness detecting device capable of easily detecting the thickness of a paper sheet without providing an exclusive sensor etc. and a printer, in a paper thickness detecting device used for a printer capable of printing on the paper sheet having a different thickness and the printer. CONSTITUTION: The paper sheet 54 is abutted on the clearance between resister rollers 55 and 56 for feeding the paper, the rollers 55 and 56 are rotated to carry the paper 54 and its passage is detected by a paper passage sensor 57. Then, the time from the drive of the resister rollers 55 and 56 to the detection of the passage of the paper 54 by the sensor 57 is detected to detect the thickness of the paper 54 in accordance with the detected time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper thickness detecting method,
In particular, the present invention relates to a sheet thickness detecting method used in a printing apparatus that prints on sheets having different thicknesses.

In recent years, OA (office automation)
In the field of equipment, the quality of equipment is being improved, and in particular, printers and the like are required to print with high image quality on various types of paper.

In order to achieve high image quality in a printer, it is necessary to control the transfer current, the fixing temperature, etc. according to the thickness of the paper. For this purpose, it is necessary to accurately detect the thickness of the paper.

[0004]

2. Description of the Related Art FIG. 6 is a block diagram of a conventional printing apparatus.

The printing device 18 comprises a paper feed cassette 53 for feeding paper 54, a process unit 2 for developing and transferring.
6. A fixing device 71 for fixing printing. One sheet of paper 54 set in the paper feed cassette 53 is taken out by the pick roller 12, and the registration roller 5 is stopped rotating.
5, it is abutted against the registration roller 56 and is registered. When a print command is input to the printing device 18 from a host computer or the like, the registration rollers 55 and 56 are driven,
The sheet 54 is sent to the process unit 26. The process unit 26 includes a drum unit 72 that applies the toner 10 to the paper 54 according to the print pattern, and a developing unit 73 that supplies the toner 10 to the drum unit 72 according to the print pattern.

The drum unit 72 includes a photosensitive drum 76 and a photosensitive drum 7 to which the toner 10 adheres according to a print pattern.
6, a transfer roller 77 for transferring the toner 10 adhering to the photosensitive drum 76 to the paper 54, a drum unit cover 15 for covering the drum unit 72 and preventing the toner 10 from scattering.

The developing unit 73 has a developing unit frame 16 for accommodating the toner 10, a paddle 79 for scraping out the toner 10 from the developing unit frame 16, the toner 10 attached according to a print pattern, and is provided so as to face the photosensitive drum 76. And a developing roller 78 that generates a print pattern and transfers it to the photosensitive drum 76.

Toner 10 developed on the photosensitive drum 76
Is transferred to a sheet by the transfer roller 77, and then the sheet 54 is sent to the heat fixing device 71 and the toner 1 transferred to the sheet 54 is transferred.
Fix 0. The fixing device 71 applies heat to the paper 54 on which the toner 10 is transferred as a print pattern in the process unit 26, and keeps the temperatures of the heat rollers 74 and 75 and the heat rollers 74 and 75 for fixing the toner 10 on the paper 54 constant. Fuser cover 13, 14, fuser cover 13,
14, a heat insulating material 27 arranged inside the fixing device 71 for keeping the inside of the fixing device 71 in a heat insulating state, and a temperature sensor 17 for monitoring the internal temperature.
It is composed of

The sheet 54 on which the toner 10 is fixed by the fixing device 71 is discharged to the outside while being guided by the sheet guide rib 11.

Mechanisms such as the pickup roller 12, the registration rollers 55 and 56, the process unit 26, and the fixing device 71 are connected to a controller 81, and the controller 81 controls the conveyance of the paper 54, the transfer of toner, and the fixing. It

The elements that greatly affect the printing quality are the transfer roller 77 and the thermal transfer device 71. The transfer roller 77 passes a sheet of paper by passing a positive current and sucks the negatively charged toner 10 on the photosensitive drum 76 to the sheet of paper 54. However, if the sheet of paper 54 is thick, the suction force becomes weak and the transfer rate decreases. Further, when an excessive current is applied to thin paper, abnormal discharge occurs and the toner 10 scatters, which disturbs the transferred print. The heat fixing device 71 warms the paper and the toner 1
Although 0 is melted by heat to be fixed on the paper, if the paper is thick, it is hard to warm and the fixing ratio is lowered. Further, when heat is applied to thin paper more than necessary, the paper is curled, which may cause a conveyance jam.

From the above, the transfer current corresponding to the paper thickness,
It is necessary to control the fixing temperature, and in order to realize this, the detection of the paper thickness is an important point.

In the conventional paper thickness detection method, as shown in FIG. 6, the thickness (step) of the paper is passed through the sensor lever 51, the thickness is enlarged by the lever ratio, and the movement amount of the lever 51 is detected by the sensor 52. What was done was common. Also, JP-A-59-40
674, JP-A-58-17468, JP-A-3-5058
There was a detection scheme shown at 5.

FIG. 7 shows Japanese Patent Laid-Open Nos. 59-40674 and 5
8 is a block diagram of an example of a paper thickness detection mechanism shown in FIG. In the figure, reference numerals 101 and 102 denote paper feed rollers. A rotation shaft 103 of the paper feed roller 101 is pivotally supported on one end of a displacement measuring plate 104. Displacement measuring plate 104
Is rotatably arranged around a rotary shaft 105 attached to the other end, and the paper feed roller 101 is pressed against the paper feed roller 102 by a spring 106.

The displacement sensor 1 is provided at one end of the displacement measuring plate 104.
07 is in contact with the paper feed roller 101, and the vertical movement of the paper feed roller 101 can be detected.

The paper feed roller 101 is a paper feed roller 101.
Since the sheet moves up and down according to the thickness of the sheet passing between the sheet feeding roller 102 and the sheet feeding roller 102, the detection of the sheet thickness is detected by detecting the vertical movement by the displacement sensor 107.

FIG. 8 is a block diagram showing an example of a paper thickness detecting mechanism disclosed in Japanese Patent Laid-Open No. 3-50585. In the figure, reference numeral 201 denotes a base plate 201. A laser light generator 202 and a light receiver 203 are arranged above the main plate 201, as shown in FIG.
As shown in (a), the paper 204 is the laser light generator 20.
When the sheet 2 is not on the lower side of the sheet 2, the reflected light from the main plate 201 is supplied to the light receiving device 203, and as shown in FIG.
When 04 is positioned below the laser light generator 202, the light reflected by the paper 204 is supplied to the light receiver 203.

When the thickness of the sheet 204 changes, the incident position of the reflected light on the light receiving device 203 changes, so that the light receiving device 20
The incident paper 2 is detected by detecting the incident position of the reflected light at 3.
A thickness of 04 was detected.

[0019]

However, according to the conventional method shown in FIG.
Printing device shown in JP-A-59-40674 and JP-A-58
In 17468, since the step that makes the thickness of the sheet equal to the thickness of the sheet is mechanically amplified and the mechanical change due to the step is converted into an electric signal to detect, the positioning of the detection unit with respect to the sheet is performed. There was a problem that it was necessary to do it accurately.

Further, the printing apparatus shown in FIG.
40674, JP-A-58-17468, JP-A-3-50
In 585, since it was necessary to provide a dedicated sensor for detecting the thickness of the paper, there was a problem such as an increase in cost.

Furthermore, the printing device shown in FIG.
-40674, JP-A-58-17468, JP-A-3-5
The 0585 has a problem in that the warp of the sheet may be detected, and the thickness of the sheet may be erroneously recognized.

The present invention has been made in view of the above points, and an object of the present invention is to provide a paper thickness detecting method capable of easily detecting the paper thickness without providing a dedicated sensor or the like.

[0023]

FIG. 1 shows the principle of the present invention. The rotating roller 1 is rotatably held and holds the sheet 1 for conveyance.

The driving means 3 rotates the rotary roller.

The passage detecting means 4 is provided on the side of the rotating roller in the sheet conveying direction and detects passage of the sheet conveyed by the rotating roller.

The time detecting means 5 drives the driving means in a state where the sheet is abutted against the sheet holding portion of the rotating roller,
The rotation roller is rotated, and the time from the conveyance of the paper to the detection of the passage of the paper by the passage detecting means is detected.

The thickness detecting means 6 detects the thickness of the paper according to the time detected by the time detecting means.

According to a second aspect of the present invention, in a printing apparatus that conveys a printing sheet by the sheet conveying mechanism and prints on the printing sheet, the printing is performed according to the sheet thickness of the printing sheet detected by the thickness detecting means. Controls printing on paper.

According to a third aspect of the present invention, the fixing temperature is controlled as the printing control.

According to a fourth aspect, transfer current is controlled as the printing control.

[0031]

According to the first aspect of the present invention, the rotating roller is rotated while the sheet is in contact with the nip of the rotating roller, the sheet is fed, and the time when the sheet is detected by the passage detecting means is detected. , Determine the paper thickness. Since cardboard as shown in FIG. 1 in a state where the paper is in contact with the clamping hole of the rotating roller, the contact position between the rotation roller at the thin different, when a paper feed in the same manner is performed, time t ₂ -Shift by t ₁ . The sheet thickness can be determined from this deviation.

As described above, according to the present invention, since the sheet thickness itself is not detected, a mechanism such as a sensor and a sensor lever is unnecessary.

According to the second aspect of the present invention, by performing the printing control of the printing apparatus using the sheet thickness detecting apparatus of the first aspect, it is possible to perform printing according to the sheet thickness without increasing the cost, and it is possible to perform high printing regardless of the sheet. Quality printing is possible.

According to the third aspect, the sheet thickness detecting device according to the first aspect detects the sheet thickness, and the fixing temperature is controlled as the print control according to the sheet thickness, so that high-quality printing can be performed without an increase in cost. It is possible.

According to the fourth aspect, by controlling the transfer current as the printing control according to the sheet thickness, it is possible to perform high quality printing without increasing the cost.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 shows a schematic configuration diagram of an embodiment of the present invention. 7, those parts which are the same as those corresponding parts in FIG. 7 are designated by the same reference numerals, and a description thereof will be omitted.

In this embodiment, the paper thickness detecting lever 51 and the sensor 52 shown in FIG. 7 are eliminated, and the paper thickness detection is performed by the processing in the control unit 81 using the conventional registration rollers 55 and 56 and the paper passage sensor 57. To do.

FIG. 3 shows a block diagram of the controller 81 according to one embodiment of the present invention. The control device 81 includes a mechanism control board 64 that controls the mechanical operation of the entire printing device, a roller drive board 61 that drives rollers such as registration rollers 55 and 56, and a heat fixing heater driver boat 62 that heats the heater roller 74 of the fixing device 71. , A transfer current driver board 63 that supplies a transfer current to the transfer roller 77.

The mechanism control board 64 is a roller drive board 6 in response to a print command from a host computer or the like.
1, controlling the heat fixing heater driver 62 and the transfer current driver board 63.

Further, the mechanism control board 64 is connected to the paper passage sensor 57, and the paper passage sensor 5 is connected.
7, it is determined whether or not the paper is normally conveyed to the drum unit, the conveyance state of the paper 54 is monitored, and the paper thickness is detected according to the detection signals from the built-in timer 64a and the paper passage sensor 57.

Next, the operation of the embodiment of the present invention will be described. FIG. 4 is an operation flowchart of one embodiment of the present invention,
FIG. 5 shows an operation explanatory diagram of one embodiment of the present invention.

When a print command is input from the outside of the host computer or the like, the mechanism control board 64 controls the roller drive board 61 to rotate the registration rollers 55 and 56 and activate the built-in timer 64a (step S1). , S2). At this time, the end portion of the sheet 54 is set in advance in a state of being in contact with the nip S of the registration rollers 55 and 56.

The mechanism control board 64 monitors the passage sensor 57, detects the passage time of the passage sensor 57 for the paper 54, and determines whether the paper 54 is thick paper 54a or thin paper 54b (step S3).

As shown in FIG. 5, in the case of the thick paper 54a, the thick paper 5 is inserted into the wedge-shaped holding port S of the registration rollers 55 and 56.
Since the holding port S has a wedge shape in the state in which 4a is abutted, the upper and lower ends of the thick paper 54a come into contact with the front side of the holding port S, and the thin paper 54b is inserted to the back of the holding port S. Will be done.

That is, the position where the paper 54 is set differs depending on the thickness of the paper. For example, the thick paper 54a is at the position P ₁ and the thin paper 54b is at the position P ₂ .

Therefore, if the registration rollers 55 and 56 are driven in the state as shown in FIG. 5, the time required to reach the passage sensor 57 is t ₁ for the thick paper 54 a and the thick paper 54 a for the thin paper 54 b. Is time t ₁ and thin paper 5
In 4b, since the amount of movement to the passage sensor 57 is smaller than that of the thick paper 54a, the time t ₂ (<t ₁ ) is sufficient.
The time required to reach the passage sensor 57 varies depending on the thickness of the.

Now, returning to FIG. 4 again, the description will be continued.
Therefore, a predetermined time T for separating the thick paper 54a and the thin paper 54b is set in advance on the mechanism control board 64, and the paper 54 is separated from this time T and the registration roller driving time.
Is compared with the time t until the paper passes through the passage sensor 57 to judge whether the paper is thick paper 54a or thin paper 54b. Here, if the time t is greater than the time T, the passage sensor 57
It is determined that the paper is a thick paper 54a because it is a paper having a large movement amount to, and if the time t is shorter than the time T, it is a paper that has a small movement amount to the passage sensor 57, and thus is a thin paper 54b.

When it is determined in step S3 that the card is thick paper 54a, the mechanism control board 64 sets the control mode to the thick paper mode for optimally printing the thick paper, and the heat fixing heater driver board 62 is set to the heater roller 7 of the fixing device 71.
4 is driven at a high temperature and the transfer current driver board 63 is controlled so that the current supplied to the transfer roller 77 is increased, and the printing is held until the printing by the print command is completed (steps S4 to S7).

When it is determined in step S3 that the paper is thin paper 54b, the mechanism control board 64 sets the control mode to the thin paper mode for optimally printing the thin paper, and the heat fixing heater driver board 62 is used as the heater roller of the fixing device 71. The transfer current driver board 63 is controlled so as to reduce the current supplied to the transfer roller 77, and the state is maintained until the printing by the print command is completed (steps S8 to S11). ).

After printing, the mechanism control board 64
Shifts to the standard printing mode for preparing for the next printing (step S12).

In the print preparation mode, the mechanism control board 64 controls the roller drive board 61 to drive the pick roller 12, pull out the paper from the tray 53, and hit the end portion of the paper with the nipping opening S of the registration rollers 55 and 56. Contact.

As described above, when thick paper is used, a large transfer current is set to obtain a sufficient toner suction force, and the transfer rate is maintained optimally. When thin paper is used, a small transfer current is used to increase the toner suction force. It suppresses and keeps the transfer rate optimal, prevents the toner from scattering due to abnormal discharge, and improves the image quality.

Further, by setting the temperature of the heater of the fixing device high when the paper is thick, the thick paper is set to the optimum temperature for fixing the toner to improve the fixing rate and improve the image quality. When the paper is thin, the temperature of the heater of the fixing device is set low. By doing so, it is possible to prevent the thin paper from overheating, prevent the paper from curling, and prevent the occurrence of conveyance jams.

Further, the registration rollers 55 and 56 and the sensor 57 for detecting the conveyance jam, which are conventionally provided, are required to detect the thickness of the sheet 54, and a dedicated sensor or the like is required to detect the sheet thickness. Since it is possible to detect the paper thickness with a small number of parts, the assembling property can be improved and the cost can be reduced.

[0055]

As described above, according to the first aspect of the present invention, since the paper thickness can be detected without providing a dedicated sensor, precise positioning of the sensor or the like is not required and the assembling property is improved. At the same time, since it does not require a dedicated sensor or the like, it has features such as cost reduction.

According to the second aspect, by performing the print control using the sheet thickness detecting device according to the first aspect, the print control according to the sheet thickness can be performed without providing a dedicated sensor or the like, so that the assemblability is improved. It is possible to improve the print quality without deteriorating the print quality and increasing the cost.

According to the third aspect, the sheet thickness detecting device according to the first aspect detects the sheet thickness, and the fixing temperature is controlled according to the sheet thickness. Therefore, printing can be performed at the fixing temperature optimum for the sheet thickness. It has features such as improved assembly quality and improved print quality without increasing costs.

According to the fourth aspect, since the sheet thickness is detected by the sheet thickness detecting apparatus according to the first aspect and the transfer current is controlled, it is possible to perform printing with a transfer current most suitable for the sheet thickness, which may deteriorate the assembling property. It has features such as improving print quality without increasing costs.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a schematic configuration diagram of an embodiment of the present invention.

FIG. 3 is a block diagram of a main part of one embodiment of the present invention.

FIG. 4 is an operation flowchart of one embodiment of the present invention.

FIG. 5 is an operation explanatory diagram of the embodiment of the present invention.

FIG. 6 is a schematic configuration diagram of a conventional example.

FIG. 7 is a configuration diagram of another example of the related art.

FIG. 8 is a configuration diagram of another example of the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 rotating roller 2 paper 3 driving means 4 passage detecting means 5 time detecting means 6 paper thickness detecting device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tsutomu Honma 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Limited

Claims (4)

[Claims] 1. A rotary roller which is rotatably held and holds and conveys a sheet, drive means for rotating the rotary roller, and a rotary roller which is provided in the conveying direction of the sheet. Is provided in a sheet conveying mechanism having a passage detecting unit that detects passage of the sheet conveyed by the drive unit, and drives the driving unit in a state in which the sheet is abutted against the sheet holding portion of the rotating roller. Depending on the time detected by the time detecting means, the time detecting means detects the time from the rotation of the rotating roller to convey the paper until the passage detecting means detects the passage of the paper. A sheet thickness detecting device for detecting the thickness of the sheet. 2. A printing apparatus that carries printing paper by the paper carrying mechanism and prints on the printing paper, according to the paper thickness of the printing paper detected by the thickness detecting means. Printing control is performed.
A printing apparatus using the described paper thickness detection device. 3. The printing apparatus according to claim 2, wherein the printing control is a fixing temperature control. 4. The printing apparatus according to claim 2, wherein the printing control is transfer current control.