JPH02300055A - Jam detecting device of media sheet - Google Patents

Abstract

PURPOSE:To reduce the cost of the device by using a mark to indicate the sensitivity of a media sheet and the like and a reading device to read the mark concurrently to a jam detecting device. CONSTITUTION:When the autoloading is started, a timer is started to clock the time until the mark of a media sheet 3 is read. When no jamming is generated, the time from the starting of the autoloading to the time when the mark is read by a reading device 8 is constant. In other words, since the length from the tip end of the media sheet 3 to the mark is constant, the necessary time is determined. And, the time up to the mark reading actually clocked is compared with the necessary time in the normal condition. That is, if the media sheet 3 generates a meandering, a shrink, or the like, the time the mark reaches to the reading device 8 is changed, and in such an occasion, it is decided that a jamming is generated.

Description

Detailed Description of the Invention (a) Industrial Application Field This invention detects a jam when loading a roll-shaped media sheet wound around a supply shaft into an image forming apparatus (during autoloading). Regarding equipment.

Conventional technology In image forming apparatuses that form images using photosensitive and pressure-sensitive media sheets, unused media sheets are wrapped around a supply shaft and placed inside a cartridge in order to protect them from external light and pressure. It is stored. This media sheet goes through an image forming process, that is, an exposure process, a pressure development process, etc., and then is wound onto a take-up shaft.When the media sheet is initially set, it is automatically pulled out (autoloading). ) Exposure process department.

The film is wound up on a winding shaft after passing through a pressure development process section and the like.

During this autoloading, jamming of the media sheet may occur, and jamming is particularly likely to occur in the pressure developing section because high pressure is applied thereto. In order to detect such jams, conventional media sheet detection sensors are installed on both sides of the media sheet conveyance path, and when the sensor is turned on or
Jam detection was performed depending on the off state. Specifically, it has been common practice to provide optical sensors on both sides of the media sheet conveyance path, and if they turn on at the same time, it is normal, and if there is a difference in the on timing, it is determined that a jam has occurred.

(C1 Problem to be Solved by the Invention However, in the conventional device, a large number of jam detection sensors are required, resulting in an increase in cost.

Therefore, an object of the present invention is to provide an inexpensive jam detection device.

(d) Means for Solving the Problem By the way, photosensitive and pressure-sensitive media sheets have variations in photosensitive characteristics and the like from production lot to production lot. Therefore, a mark indicating the characteristics of each lot is displayed on the leading edge of the media sheet, and the mark is read during autoloading to perform color correction, etc.

In this invention, the above-described mark and mark reading device are also used as a jam detection device to reduce the cost of the device, and the mark indicating the characteristics etc. is displayed at a predetermined length from the leading edge of the media sheet, and the automatic A timer is provided that starts when loading starts and stops when the mark reading device detects a mark, and furthermore, jam detection is performed by comparing the time required from the start of autoloading to reading the mark under normal conditions with the time measured by the timer. A feature of the invention is that a means is provided for carrying out the procedure.

(e) Function In the jam detection device of the present invention, when autoloading is started, a timer starts and measures the time until the mark is read. When no jam occurs, the time from the start of autoloading until the mark is read is constant.

That is, since the length from the leading edge of the media sheet to the mark is determined, the required time is determined. Note that the feeding speed of the media sheet is naturally kept constant due to the drive system of the apparatus.

In this device, the time it takes to actually read the mark is compared with the time required under normal conditions (when no jam occurs). That is, if meandering, jamming, etc. occur in the media sheet, the time it takes for the mark to reach the mark reading device will change, and in such a case, it will be determined that a jam has occurred.

(FIG. 3 is a schematic front view of a copying machine that forms an image using a media sheet.

On the top of the copying machine body is a document table 1 made of transparent glass.
is provided. A document A to be copied is placed on a document table l. An optical system including light sources 21, 22, mirrors 23 to 26, lenses 27, and a filter 28 is provided below the document table 1, and the optical system scans the document A on the document table 1 and sends the reflected light to an exposure section, which will be described later. I'm trying to guide you. Note that filter 2
Reference numeral 8 has a plurality of filters having different transmission wavelengths and transmittances, and a combination of these filters performs color correction of reflected light from the document. Further, the combination of filters is set based on sensitivity characteristics, etc., which differ for each manufacturing loft of the media sheet.

The central left side of the copying machine main body is a storage area for the media sheet 3. The media sheet 3 is a light-reflective sheet made of aluminum or the like, on which microcapsules (010 to 20 μm) encapsulating a color-forming dye 2 photocurable material are coated. Since this sheet is photosensitive and pressure sensitive, it is wound around the supply shaft 41 and stored in the storage chamber 42 of the media cartridge 4 made of a light-shielding material. The media cartridge 4 also has a take-up shaft 43. A used media sheet is wound onto the take-up shaft 43.

The media cartridge 4 is attached to the packet 5. FIG. 4 is a perspective view of the packet 5. The packet 5 can be pulled out toward the front of the copying machine body using sliders 51 and 51. packet 5
has the shape of a box with an open top, into which the media cartridge 4 can be inserted from above. The figure shows a state in which the media cartridge 4 is fitted into the bucket 5. A tractor roller 51 is provided at the upper right end of the bucket. The tractor roller 51 is connected to a main motor (not shown) and is rotated at a constant speed. The tractor roller 51 has a plurality of pins 51 at both ends.
a, which is adapted to engage with a hole provided in the league sheet at the leading end of the media sheet.

FIG. 5 is a view of the back side of the leading end of the media sheet 3, and the leading end of the media sheet 3 is provided with a league sheet portion 31 made of a stiff resin sheet. The league seat portion 31 is slightly wide, and a plurality of holes 32 are formed at both ends thereof. This hole 32 engages with the tractor roller 51. Further, a guide hole 33 is formed at the center of the tip end of the league seat portion 31. This engages a guide pin of the bucket which will be described later. Furthermore, marks 34 indicating photosensitive characteristics, etc. are displayed on the reader sheet portion 31. The mark 34 is displayed at a position exactly L length from the leading edge of the media sheet.

The tractor roller 51 has guide members 5 l b, , 5
lb is rotatably provided and is adapted to hold down the wound media sheet. Furthermore, guide pins 52, 52 are provided on the left side of the tractor roller 51 for positioning the media sheet. As shown in the figure, after the media cartridge 4 is installed in the bucket 5, the media sheet 3 is pulled out by hand and the guide hole 33 is hooked onto the guide pin 52, and the hole portion 32 is hooked onto the pin 51a of the tractor roller 51. Then, the guide member 51b is rotated to press the leader sheet against the tractor roller 51.

When the bucket 5 is pushed into the main body of the copying machine in this state, the tractor roller 51 rotates and autoloading is started. Note that the guide pins 52, 52 are designed to go down when the bucket 5 is pushed into the main body of the copying machine, so there is no problem in conveying the media sheet.

An exposure table 6 and a pressure developing roller 7 are provided on the right side of the bucket 5. When the bucket is attached to the main body of the copying machine, the media sheet whose leading end is hung on the tractor roller 51 is wound onto the take-up shaft 43 via the exposure table 6, the pressure developing roller 7, etc. by auto-loading. A reflective photo ink converter 8 is provided on the back surface of the exposure table 6. The photo ink printer 8 detects the mark 34 displayed on the media sheet. Here, the loading speed of the media sheet 3 during autoloading is constant, and from the start of autoloading of the media sheet until the photo ink printer 8 reads the mark 34 (
The time (until the media sheet is fed by L) is also constant. This device uses this to detect jams in media sheets.

FIG. 2 is a time chart showing an example of mark detection.
The figure (A) shows the normal state, and the figure (B) shows the state when a jam occurs. °When autoloading is performed normally, the mark is detected T hours after autoloading starts, but if there is a jam, for example, the conveyance direction of the media sheet is misaligned, the mark is detected after t8 hours, that is, the mark is detected normally. Marks are detected faster than when the mark is detected. Note that if the media sheet is fed diagonally, the mark reading timing will often become faster (and if the media is jammed, the mark will not be detected).

FIG. 1 is a flowchart showing the processing procedure for detecting a jam during autoloading.

When the media cartridge is set and the bucket 5 is inserted into the main body of the copying machine, autoloading is started (nl→n2). A timer t starts at the same time as this autoloading starts, and measures the time until the photo interrupter 8 detects the mark 34 (n3→n4→
n5). The time t until the mark 34 is detected is
If it is slightly longer than the autoloading time T under normal conditions (within α), it is assumed that normal winding has been performed and the mark is read (n6 → n7 → n8), and winding of the leading edge of the media sheet is detected. If no mark is detected even after the elapse of time, it is determined that a jam has occurred, and autoloading is stopped (n11→n12). Note that this α time is a delay time long enough to determine that the media sheet is jammed.

In this jam detection device, it is desirable that the mark 34 be displayed near the rear end of the league sheet portion 31. This is because the mark is read at a timing immediately before or after the leading edge of the media sheet is wound up on the take-up shaft 43, and jams do not occur after the mark is read.

(g1 Effects of the Invention As described above, in this invention, the mark representing the sensitivity characteristics of the media sheet and the reading device for reading the mark are also used as the jam detection device, so the cost of the device can be reduced. .

[Brief explanation of drawings]

Fig. 1 is a flowchart showing the processing procedure for detecting a jam during autoloading, and Fig. 2 is a diagram showing the mark detection timing of the mark reading device. I'm sorry for the jam condition. FIG. 3 is a schematic front view of a general copying machine using a media sheet, FIG. 4 is a perspective view of a packet including the media sheet, and FIG. 5 is a diagram of the leading end of the media sheet. 3-media sheet, 4-media cartridge, 5-
packet, 6-exposure table, 7-pressure developing roller, 8-mark reading device, 34-mark, 43-winding shaft.

Claims (1)

[Claims] (1) Equipped with an auto-loading mechanism that automatically feeds the media sheet wound around the supply shaft and winds it onto the take-up shaft, and displays a mark indicating the photosensitive characteristics etc. on the leading edge of the media sheet, and a mark reading device In an image forming apparatus that reads the mark during autoloading, the mark is displayed at a position a predetermined length from the leading edge of the media sheet, and starts when autoloading starts and stops when the mark reading device detects the mark. A media sheet jam detection device, comprising: a timer; and means for detecting a jam by comparing the time required from the start of autoloading to mark reading in normal conditions with the time measured by the timer.